Skip to main content

Who We Are

Our Care Team

Our Care Team

Donnie Yance, MH, CN, along with naturopathic physician Dr. Susan Saccomanno and certified herbalist Oscar Sierra, offer clinical support and expert care in evidence-based wholistic health services for anyone facing chronic illness or seeking guidance for lifelong wellness. Applying a collaborative approach to healthcare, Donnie, Dr. Susan and Mr. Sierra meet weekly to review client cases and protocols, providing an effective and personalized approach for each individual. This means you benefit from the knowledge, skillsets, and forty years of combined clinical experience of our care team. As a Mederi client, you get the best of our team collaboration, while also receiving direct care from the practitioner in charge of your case.


Donald R. Yance Jr. MH, CN, RH (AHG), SFO

Donald (“Donnie”) Yance

Donald (“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 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. 

After decades of extensive research and clinical practice, Donnie has developed a unique approach to healing, which he has named the Eclectic Triphasic™ Medical System (ETMS). Now also practiced as Mederi Medicine / Mederi Care, 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. 

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 Foundation’s on-line research database. 

Donnie is also the founder and formulator of Natura Health Products, for which he has created a unique line of therapeutic-grade botanical and nutritional supplements. The current Natura portfolio consists of over thirty 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, LAc

Susan Saccomanno ND, LAc, Mederi's Senior Practitioner, has over fourteen 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 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 eight years. 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. In addition to her work in integrative cancer care, she has a decade of experience treating acute and chronic illnesses such as:

  • Allergies 
  • Arthritis 
  • Asthma 
  • Auto-immune illnesses 
  • 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.


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 has been a Mederi Medicine practitioner since completing Mederi’s advanced level clinical training course in the Eclectic Triphasic Medical System (ETMS/Mederi Care) with Donnie Yance in 2012. 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

Learn more about our care team and our clinic:

© 2021 Mederi Foundation
Charitable Disclosures

Powered by Firespring

The information on this website has not been evaluated by the FDA, nor does it constitute medical advice. We do not aim to treat, cure, or prevent any illness or disease. We recommend consulting with a qualified health care professional if you have a medical condition, are taking medications, or if you are pregnant or nursing.