Our Care Team
Experience Collaborative, Personalized Care with the Mederi Care Team
Our expert Care Team provides clinical support and evidence-based holistic health services for individuals navigating cancer, chronic illness, or seeking long-term wellness. Rooted in a whole-systems approach, we combine the best of botanical medicine, nutrition, and integrative therapies to support healing at every level—mind, body, and spirit.
What sets us apart? Every Mederi client benefits from a collaborative care model. Our practitioners meet weekly with founder Donnie Yance, MH, CN, to review cases and treatment plans—bringing together over 125 years of combined clinical experience to ensure a highly personalized and effective approach to your care.
Your practitioner works closely with you and, when appropriate, coordinates with your primary care physician or medical team to provide truly comprehensive support.
Let’s Connect – Schedule a Complimentary Discovery Call
We understand how important it is to feel confident in your care. That’s why we offer a free 15-minute Meet-and-Greet call with one of our experienced practitioners—Dr. Kristin Roos (ND), Dr. Rachel Stricker (ND), or Dr. Jason Miller (DACM, LAc).
These introductory calls are a chance to connect, ask questions about our approach, and explore if we’re the right fit for you. (Please note: no medical advice or treatment plans can be offered during this time due to HIPAA guidelines.)
To schedule your call, please contact our office at 541-488-3133 or send an email. (Please note that due to HIPAA, our practitioners cannot give medical advice or offer treatment plans during these 15-minute meet-and-greets.)
Ready to begin your healing journey?
If you're ready to become a patient, simply fill out our short inquiry form here.
Donnie Yance, CN, RH (AHG), SFO
Donnie Yance is an internationally known master herbalist and nutritionist. He received his herbal training through Sequoia College and is a professional member of the American Herbalists Guild. He was trained as a clinical nutritionist through the National Institute of Nutritional Education and holds certification through the National Association of Nutrition Professionals. He is also professed as a Secular Franciscan (SFO), which equips him with the breadth and wisdom to touch on the spiritual aspects of healing.
Donnie is renowned for his extraordinary knowledge and deep understanding of the healing properties of plants and nutrition, as well as epigenetics, laboratory medicine, oncologic pathology, and molecular oncology. He conducts his clinical practice at the Mederi Center in Ashland, Oregon and teaches at Mederi Academy, a world-class online training program in integrative oncology and health optimization. Mederi Academy offers a robust curriculum on the Mederi Care methodology, a unique approach to health and healing developed by Donnie that combines the latest scientific research with the wisdom of ancient healing traditions. Mederi Care (also known as the Eclectic Triphasic™ Medical System or ETMS) consists of a wholistic diagnostic and therapeutic methodology rooted in American Eclectic herbal tradition, constitutional energetics and contemporary clinical nutrition – continuously updated and honed with the latest scientific research at the molecular, cellular and genomic levels. Donnie is certified as a Mederi Care Practitioner and imparts his clinical knowledge of this integrative approach to patient care through our online certification program.
Donnie has authored two books, Herbal Medicine, Healing and Cancer and Adaptogens in Medical Herbalism: Elite Herbs and Natural Compounds for Mastering Stress, Aging and Chronic Illness. In addition, he has been involved in authoring and co-authoring dozens of articles that have appeared in major industry publications and national journals. On the education side, each year Donnie gives several lectures across the USA at major hospitals and conferences for both patients and health care providers, as well as making radio appearances.
In 2011, the Centre for Natural Healing (now Mederi Center), where Donnie has conducted his successful clinical practice since 1992, merged with the Mederi Foundation, a 501(c)(3) organization established by Yance in 2005. ETMS is the care model employed by the Mederi Center's clinical practice team and the Foundation’s professional educational training and clinical research programs. Over the past two decades, Donnie has built a library of well-established, world-class research on the medicinal value and multifaceted interactions of over one hundred botanicals and their key constituents, with major emphasis in the area of Oncology. This incredible collection will be available to health care professionals through the Mederi Academy's online research database.
Donnie is also the founder and formulator of Natura Health Products, a professional product line of therapeutic-grade botanical and nutritional supplements. The current Natura portfolio consists of over forty formulations derived from botanical and nutritional agents acquired from around the world. These products have made a significant contribution to his tangible success in improving the health of his patients, specifically by providing therapeutic amounts of key ingredients that would otherwise be unattainable anywhere in the world.
Susan Saccomanno, ND, MSOM
Susan Saccomanno ND, MSOM, Mederi's Senior Practitioner, has over fifteen years of experience as a family physician with a specialty in wholistic cancer care and chronic illness. Prior to joining Mederi Center in 2014, she had a family practice in Portland, Oregon. As a Naturopathic physician and Chinese medicine practitioner, Dr. Susan has a unique skill set that enables her to assess health from both Western and Eastern perspectives.
Susan received her Naturopathic Doctorate and Master of Science in Oriental Medicine degrees from National University of Natural Medicine in 2006, with a pre-med Bachelor of Arts through Appalachian State University. She also studied photography at Syracuse University. Dr. Susan has completed all three levels of the Mederi Care/ETMS Clinical Training seminars. Through her long-standing professional affiliation as a clinical associate of Donnie Yance, Dr. Susan has applied the ETMS methodology in clinical practice for over ten years and is a Certified Mederi Care Practitioner. In 2020, she completed a 2-year program to deepen her knowledge of Chinese herbology.
Dr. Susan is passionate about helping people achieve vibrant health. She understands that untangling the mass of information that confronts patients can be confusing, and strives to create a comprehensive strategy tailored to each person’s unique needs, while emphasizing a plan that is manageable and supports the patient’s quality of life. In cancer care, Dr. Susan designs treatment plans that enhance mainstream therapies, with the goal of minimizing side effects and preventing future occurrences.
“My goal with patients is to deliver comprehensive care that incorporates botanical medicine with highly individualized support for the best possible clinical outcomes.” - Dr. Susan Saccomanno
Dr. Susan was drawn to the Mederi Care/ETMS model because of its elegant approach to treating the whole person, including day-to-day health, lab work, and if applicable, the tumor microenvironment. Her patient treatment plans are created using this model, which applies the art and science of botanical medicine as well as impeccable clinical care. This ensures that all aspects of health and illness are addressed.
Being a primary care physician means Dr. Susan can help unravel complex health issues and support patients in creating positive, long-term changes in health. She has over fifteen years of experience treating acute and chronic illnesses such as:
- Allergies
- Arthritis
- Asthma
- Auto-immune illnesses
- Cancer
- Colds and flu
- Diabetes
- Digestive Problems
- Fatigue, brain fog
- High cholesterol patterns
- Hyperglycemia, hypoglycemia
- Hypothyroid/hyperthyroid
- Insomnia
- Men’s health concerns
- Migraines
- Sinusitis
- Women’s health issues
To learn more about what a Naturopathic Doctor is, please click here.
Jason Miller, DACM, LAc
Dr. Jason Miller, DACM, LAc is a doctor of acupuncture and Chinese medicine, medical educator, lecturer, writer, formulator, and musician. In 2005, he graduated from the Oregon College of Oriental Medicine's, "Master of Acupuncture and Oriental Medicine" program, and then in 2018 completed his "Doctor of Acupuncture and Chinese Medicine" degree at the Pacific College of Health and Science. Post-graduation from OCOM in 2005 he spent 2 months in Nanjing, China where he completed a clinical internship at Nanjing’s acclaimed, “House of Celebrity Doctors.”
For the past 20 years, Dr. Miller has devoted a large part of his time and energy to working closely with patients with cancer and chronic disease, often working collaboratively with his patients and their medical teams. He has developed an integrative approach that bridges the time-honored theory and practice of traditional Chinese medicine with modern biomedical therapies and diagnostic tools. Dr. Miller works closely with a group of distinguished colleagues and cancer experts, including Donnie Yance, CN, RH (AHG), founder of the Mederi Center, and Dr. Dwight McKee, MD, a board-certified hematologist/oncologist who has been working in the field of integrative cancer therapy for over 50 years. Dr. Miller also specializes in integrative care for diabetes, neuromuscular disorders, autoimmune disease, chronic infections, and environmental toxicity.
Dr. Miller has worked with Mederi Center for the past 18 years and he currently serves as Head of Faculty and Content Development for the Mederi Academy. He has also served as Medical Educator for Natura Health Products since 2006, where he hosts monthly webinars and interviews subject matter experts on the role of botanical and nutritional medicine in health and disease through Natura EDU.
Dr. Miller integrates a wide range of therapeutic tools, including bodywork therapy and acupuncture to resolve pain and improve health in his in-clinic patients.
For more information about Dr. Miller and his work, please visit his website at: https://drjasonamiller.com/
“My goal is to help people find ways to overcome cancer and chronic disease, to help them live happier, healthier lives, and to turn complex medical concepts into easily accessible information.” ~ Dr. Jason Miller
"My exploration of the role of botanical and nutritional medicine in oncology began with my relationship with Donald Yance, CN, RH (AHG), founder of Natura Health Products and The Mederi Center in Ashland, OR. Soon after graduating from OCOM in 2005, I began working directly with hundreds of cancer patients who were in desperate need of support and guidance through the maze of challenging decisions that a cancer diagnosis brings. Through my work with the Mederi Center, and through ongoing collaboration with long-time cancer experts Dwight McKee, Jonathan Treasure, and many others, I was brought into a community of medical practitioners and scholars that represent an unprecedented base of knowledge and wisdom in the collaborative management of cancer and chronic disease." ~ Dr. Jason Miller
Kristin Roos, ND
Dr. Kristin Roos received her Doctorate in Naturopathic Medicine from Southwest College of Naturopathic Medicine in 2015. After earning her degree, she completed a hospital-based residency in integrative oncology, where she served as part of a multidisciplinary care team, gaining extensive experience in both conventional and naturopathic approaches to cancer care. Prior to her doctoral training, Dr. Roos graduated Cum Laude with a Bachelor of Science from Minnesota State University in 2005.
Dr. Roos has over eight years of experience in integrative oncology, blending conventional therapies with complementary modalities to optimize patient outcomes. With a passion for holistic, patient-centered care, she utilizes evidence-based practices to minimize treatment-related side effects to improve quality of life, ensure safe use of natural therapies, and provide comprehensive care throughout the healing journey. Her expertise lies in managing complex medical conditions, tailoring integrative treatment plans to address the needs of each individual, and delivering compassionate, evidence-based care.
Prior to practicing at Mederi Center, Dr. Roos was a physician at City of Hope in Arizona (formerly Cancer Treatment Centers of America), a comprehensive cancer center offering leading biomedical research, treatment, and education. There she designed and managed individualized treatment plans for diverse patient populations, including complex medical cases, while integrating natural medicine with conventional therapies across various cancer types to optimize patient outcomes. In addition to her specialization in naturopathic oncology, Dr. Roos also offers integrative care for patients with other health concerns and conditions, applying holistic, patient-centered treatment strategies.
“My goal is to empower patients through education, lifestyle changes, and long-term wellness strategies, while remaining committed to the safe and effective use of naturopathic medicine in clinical settings.” ~ Dr. Kristin Roos
Dr. Roos is inspired by the Mederi Care® / ETMS model because of its unique approach to healing—combining ancient wisdom with cutting-edge science, which speaks directly to her own approach to personalized, integrative care. In addition, Dr. Roos was drawn to Mederi’s world-class Apothecary and the opportunity to collaborate with our clinical herbalists to provide customized, holistic treatment solutions that have a transformative impact on patients’ lives.
Outside of her professional work, Dr. Roos enjoys spending time with her son and their mini Goldendoodle, Gus.
Rachel Stricker, ND
Dr. Rachel Stricker is a licensed naturopathic doctor who earned her Doctorate of Naturopathic Medicine from Southwest College of Naturopathic Medicine in Tempe, Arizona. Since 2014, she’s been dedicated to providing compassionate primary care across a wide range of clinical settings. With a strong background in naturopathy and community wellness, Dr. Stricker enjoys working with diverse patient populations to support their health and well-being.
Prior to joining the care team at Mederi Center, Dr. Stricker owned and operated a private practice in Oregon and Washington for 8 years called Illumination Wellness, where she practiced primary care medicine with specialties in GI health, autoimmune disease, hormonal balance, and detoxification. In addition, she was the Wellness Director at Restore Functional Restoration, an integrative outpatient chronic pain institute in Phoenix, Arizona, the Medical Director at Quenby's Aesthetics and Wellness Center in Lake Oswego, and the Clinic Office Manager at Oregon Integrative Health in Eugene.
In addition to her Doctorate of Naturopathic Medicine, Dr. Stricker holds a Bachelor of Science degree in Psychology and Gender and Diversity Studies from Xavier University in Cincinnati, Ohio. She is also a certified yoga instructor, receiving her training at Authentic Yoga Teacher Training in Scottsdale, Arizona, and has been teaching yoga and offering personal training for the last 18 years. She uses her background in therapeutic yoga, meditation, Ayurveda, and fitness training to help individuals navigate pain, stress, mental health issues, and chronic disease. With a passion for using food as medicine, Dr. Stricker is a certified plant-based chef and teaches cooking classes with a focus on whole foods nutrition.
Dr. Stricker is currently pursuing her PhD in the Quantum Science of Health & Integrative Medicine through the University of Technology in Jaipur, India. Her research focuses on the powerful intersection of science and spirituality, exploring how this connection can lead to transformation and deep healing.
“As an advocate for holistic well-being, I am passionate about combining nutrition, herbal medicine, movement, and mindfulness practices in my approach to health. I am also deeply committed to fostering a collaborative and patient-centered approach to help guide, inspire and empower patients in their personal journey to optimal health and wellness.” ~ Dr. Rachel Stricker
Michael Hummel, ND
Dr. Michael Hummel is a board-certified Naturopathic Physician providing comprehensive care with an emphasis on natural therapies, to include general medicine, as well as specialization in integrative oncology and chronic infectious disease (including Lyme disease). He has further areas of focus in naturopathic adjustments/physical medicine, bioidentical hormone therapies, botanical medicine, nutrition, family medicine, and healthy aging.
Dr. Hummel received training in both modern allopathic medicine and chiropractic medicine before finding his calling in the individualized integrative approach of naturopathic medicine. He subsequently earned his medical degree from the Southwest College of Naturopathic Medicine. Prior to coming to Mederi Center, Dr. Hummel conducted his practice out of Envita Medical Center in Arizona, where he specialized in integrative oncology and chronic infectious disease.
Dr. Hummel also holds a Bachelors’ degree in Chemistry and a Bachelors’ degree in Biology with a pre-health emphasis from Northern Arizona University. After medical school, Dr. Hummel completed a 3-year NUNM, CNME-approved general practice residency. Dr. Hummel is well known for his contribution to botanical medicine through his creation of the Bountiful Herbs Botanical Medicine Database; which is used by thousands of physicians and herbalists worldwide.
“My passion in the field of medicine is to work with my patients to bring awareness, balance, betterment, and healing to the physical, mental, emotional, energetic, and spiritual aspects of their being. I'm thrilled to be part of the Mederi Center care team, where the core of Mederi Care encompasses this philosophy in its holistic, unitive approach to medicine.” - Dr. Michael Hummel
As a Naturopathic Primary Care Physician trained in the Mederi Care approach, Dr. Hummel uses Naturopathic principles combined with Mederi Care to unravel complex health issues and work alongside his patients to support them in creating positive, long-term changes in health. Dr. Hummel has many years of experience treating acute and chronic illnesses, including:
- Allergies
- Ageing and age-related diseases
- Arthritis
- Asthma
- Auto-immune illnesses
- Cancer
- Colds and flu
- Diabetes
- Digestive problems
- Fatigue, brain fog
- High cholesterol patterns
- Hyperglycemia, hypoglycemia
- Hypothyroid/hyperthyroid
- Insomnia
- Back pain (and other musculoskeletal/extremity pain concerns)
- Men’s health concerns
- Hormonal imbalances
- Obesity (weight loss need)
- Lyme disease
- Mold toxicities
- Environmental toxicities (Heavy Metals, Solvents, Pesticides/Herbicides)
- Migraines (and other headache types)
- Nutritional/Dietary imbalances
- Sinusitis
- Women’s health issues
To learn more about what a Naturopathic Doctor is, please click here.
Click here to watch Dr. Michael's interview with Ryan Sternagel on Going Integrative Plus (August 2023).
Oscar Sierra, Certified Herbalist, RH (AHG)
Mr. Oscar Sierra brings more than a decade of clinical experience to Mederi Center, blending Traditional Chinese Medicine with modern Functional Medicine. He holds a Bachelor of Science in Nutrition Science from the University of Georgia and is board-certified in Herbal Medicine, Acupuncture, and Biomedicine through the National Certification Commission for Acupuncture and Oriental Medicine (NCCAOM). Oscar is licensed to practice Acupuncture in the state of Georgia. He is also a registered herbalist through the American Herbalists Guild. As a Mederi Center clinician, Oscar offers the following modalities in his work with clients: Chinese Medicine, Lifestyle and Dietary Medicine, as well as Chinese, Western, and Ayurvedic Herbalism.
Oscar completed Mederi’s advanced level clinical training course in the Eclectic Triphasic Medical System (ETMS/Mederi Care) with Donnie Yance in 2012 and is a Certified Mederi Care Practitioner. His practice focus involves working with cancer patients, as well as other difficult to treat chronic autoimmune and gastro-intestinal conditions. Oscar works collaboratively with other members of our Care Team – Mederi’s founder Donnie Yance and Naturopathic Physician Dr. Susan Saccomanno.
Oscar’s approach to healing is wholistic and client-centered, keeping the focus on the client rather than the disease by carefully examining their condition, constitution, outlook, and environment. This individualized approach employs treatment strategies that are tailored to the client and incorporate both ancient evidence-based Eastern approaches, as well as aspects of progressive Functional Western Medicine. These strategies typically include diet, lifestyle, and herbs as the main therapeutic modalities as well as supplements, and an occasional healthy dose of laughter - a personal favorite healing modality for Oscar.
In addition to his clinical work, Oscar is a speaker at various state, regional, and national herbal and functional/integrative medicine conferences. He also practices and teaches Martial Arts (2nd Dan Black Belt, Chi Budo Kwon) and enjoys volunteering with group acupuncture treatments for the homeless at a free community clinic in Georgia. He is an active member of the American Herbalists Guild (AHG), International College of Integrative Medicine (ICIM), National Association of Environmental Medicine, and the Society for Integrative Oncology (SIO).
“While I am endlessly enthralled with science, I find resonance in the art of medicine. At the heart of that is connection. My role is to find that connection with clients and in turn help them become aware of connection with their True self to facilitate the deepest healing and best outcomes possible.” ~ Oscar Sierra, CH
Areas of Specialty:
- Cancer
- Autoimmune
- Gastrointestinal
- Allergies
- Insomnia
- Thyroid imbalance
- Chronic fatigue
- Diabetes
- Environmental medicine
- Cardiovascular disease
- Psycho-emotional issues, including: Stress, anxiety, depression
- Chronic pain
- Chronic fungal infections
Gloria Schwartz, ND
Dr. Gloria Schwartz is a graduate of the National College of Naturopathic Medicine and has been in practice for over 30 years. After completing a residency in women’s health, she moved to Ashland, Oregon, and opened a women’s health and home birth practice. Over the years, Gloria’s practice has transitioned with her patients, and the bustling mama and baby years have transformed into the greater complexities of chronic health care. Three decades as a family physician has enabled her to confidently treat patients at all stages of life and to appreciate the myriad factors in an individual’s life that influence states of health and disease. She has been humbled by the challenges her patients face and the courage and resilience with which they approach them.
Botanical, nutritional and homeopathic medicine are the modalities with which Gloria is most aligned. She was introduced to Mederi Medicine in 2009 and has incorporated it into her practice ever since. She consults with patients with cancer, metabolic, hormonal and autoimmune diseases, as well as those without diagnoses who are searching for health optimization. She also sees children. Gloria is particularly interested in contemporary medical research on health and longevity and incorporates it into her treatment protocols.
Gloria has a deep love of plants, medicinally, culinarily, and in nature. She enjoys spending time with her family and friends, gardening, cooking, spending time in the wild, studying medicine, and escaping into the transformational worlds of fiction.
