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Who We Are

Our Clinic Staff

Our Clinic Staff

Donald R. Yance ~ Founder, President, Mederi Center Lead Clinician

Donald “Donnie” R. Yance is a Clinical Master Herbalist and Certified Nutritionist 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 is a professional member of the American Herbalists Guild and the National Association of Nutrition Professionals. He is also professed as a Secular Franciscan, which equips him with the breadth and wisdom to touch on the spiritual aspects of healing. Donnie conducts his clinical practice at the Mederi Center in Ashland, Oregon utilizing his unique integrative model known as the Eclectic Triphasic Medical System (ETMS) or “Mederi Medicine”, which he evolved over more than twenty years of successful patient care. The ETMS model elegantly combines his passion for the latest scientific research with the wisdom of ancient healing traditions, resulting in a compassionate, creative, intelligent, and effective approach to healing. As a visionary leader, mentor, teacher, author, and healer, Donnie’s methodology has transformed thousands of lives and is carried out through the mission and programs of the Mederi Foundation.

Jennifer Yance, Co-Founder ~ Executive Director

Jennifer Yance's work at the threshold of the organization has been a key element to its growth and accomplishments. With her impassioned determination and an aura of inspiration, she oversees and directs the fundraising, clinical, research, and education programs and gracefully guides the organization in serving its mission.

Jennifer’s business acumen, effective leadership, and deep commitment to healthy living contribute to her ability to help the organization reach its highest potential for serving humanity.


Dr. Susan Saccomanno, ND, LAc ~ Senior Practitioner

Dr. Susan Saccomanno, ND, LAc holds a Doctorate in Naturopathic Medicine and a Master of Oriental Medicine both from the National College of Natural Medicine and Bachelor of Arts degrees from Syracuse University and Appalachian State University. Dr. Saccomanno has over fourteen years of experience as a primary care physician in family practice and specializes in holistic cancer care and chronic illness.

Dr. Saccomanno’s approach combines cutting edge research and Naturopathic and Chinese traditions along with the ETMS (Eclectic Triphasic Medical System). She has deep faith in the healing and regenerative powers of natural therapeutics, which plays a central role in her treatment. Susan enhances mainstream therapies to minimize side effects and to prevent future occurrences.


Oscar Sierra, RH (AHG) ~ Care Team Practitioner

Mr. Oscar Sierra 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. 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.

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.


Tia Adachi ~ Client Liaison

Tia is the Client Liaison for Donnie Yance, MH, CN. She has an impressive background in healthcare with a special focus in patient care, clinic operations management, and technical therapies. Tia has served in many diverse roles throughout her career and is passionate about integrating multi-disciplinary medical practices to provide the best possible experience and outcome for each patient.

In her involvement with direct patient care, Tia has many years of experience as a medical assistant and serving in roles that specialize in primary care, hospice, internal medicine, and naturopathic medicine. In each situation, Tia seeks to contribute to and cultivate an environment that is supportive and empowering to everyone. With her drive to foster health and healing, Tia is the ideal person to assist Donnie’s clients. Her experience aids her in tending to essential items and providing an approachable atmosphere that promotes a positive practitioner-client relationship in support of successful clinical results.


Laura Macaluso ~ Client Liaison

Laura joined the Mederi Center team in 2022 and is the Client Liaison for Susan Saccomanno, ND, LAc. Laura has worked in the health and wellness field in several capacities for years, including the "Wellness Lead" at a local natural food and healthcare products establishment, and as a yoga instructor. She shines in her role at Mederi Center, and highly values the compassionate and patient-centric care model practiced at our clinic.

Laura is the bridge between Dr. Susan and her patients, tending to all the details of this continually evolving and complex relationship. This includes many of the administrative duties that help us provide the best continuity-of-care in support of optimal and successful outcomes for Dr. Su's patients.



Lisa Newton ~ Client Liaison

Lisa is the Client Liaison for Oscar Sierra, RH (AHG), bringing over fifteen years of previous healthcare experience to the position. As the program director and head health coach at an integrative health center, she implemented wellness programs, teaching classes in health and nutrition to hundreds of people. She has also worked at medical schools all over the country as a “Standardized Patient”, helping to train medical students how to communicate compassionately and effectively with patients.

Lisa holds nutrition certifications from Bauman College and The Institute for the Psychology of Eating, and is also a breast cancer survivor. Lisa's extensive experience in the healthcare field, as well as her own personal journey with cancer, makes her the ideal bridge between Oscar and his clients. Lisa skillfully tends to all the details of this important relationship to help our clients have successful outcomes.


Taylor Appel ~ Apothecary Herbalist Supervisor

Taylor is our Apothecary Herbalist Supervisor – a position she is eminently qualified for given her background as a certified Clinical Herbalist, which she received from the Hawthorn Institute for Herbal Medicine and Ayurveda, and her bachelor’s degree from Syracuse University in Nutrition and Dietetics. As supervisor for Mederi’s compounding apothecary, Taylor is responsible for all aspects of Mederi’s apothecary operations such as having knowledge of all apothecary products and procedures, custom compounding for patients and practitioners, ordering/receiving inventory, quality control and procurement, and accurate record-keeping, ensuring AHPA Good Compounding practices are followed. Taylor is passionate about empowering individuals to discover the healing potential of herbal medicine for themselves. With her vibrant personality and whole-hearted enthusiasm for herbal medicine, she is a valued member of our clinic team.


Michael Garcia ~ Apothecary Herbalist

As our Apothecary Herbalist, Michael is responsible for supporting all aspects of apothecary operations. This includes custom compounding of teas, tonics and topicals as stated on patient/client protocols, as well as compounding stock formulas formulated by our Founder and Lead Clinician Donnie Yance. Michael is also tasked with maintaining knowledge of apothecary products, inventory restocking and tracking, accurate record keeping, and upholding the highest standard of industry compliance.

Michael has a Holistic Herbalist Certificate from Holistic Arts Institute and is currently working toward obtaining his Master Herbalist certification. An avid and passionate student of herbal medicine, Michael is also studying to become and Ayurvedic Health Practitioner.


Gretchen Roberts ~  Customer Service / Order Fulfillment Coordinator

Gretchen has been with Mederi Center since 2004 and is intimately aware of the need for timely, accurate, rapid, actionable, and documented communication between practitioners and their clients/patients.  This is especially so when it comes to knowledgeably answering order fulfillment questions about products, following Apothecary Policies & Procedures, overseeing quality assurance checks on all product orders, and archiving and maintaining accurate and up-to-date practitioner/client account information.




Diane Chasmar ~ Clinic Coordinator

Diane joined the Mederi Center team in 2019. She is an integral part in ensuring that our clinic operations run smoothly and successfully, performing a variety of administrative support and client/patient service tasks. Diane is also the hub of our client/patient reception. With her friendly, gracious demeanor and efficient work ethic, Diane handles phone and email communications, schedules appointments for multiple practitioners, and also serves as a product shipping coordinator. Diane plays a supportive role for many aspects of our organization, and strives to create a streamlined customer service experience. As the first contact for people inquiring about our patient services, we greatly appreciate Diane's kind and compassionate personality. Diane's previous professional experience includes business management, and 25 years in the publishing industry including graphic design, and photography.




Gayle Vezie ~ Bookkeeper

Gayle Vezie has been working as the bookkeeper for Mederi since 2003. She takes pride in and truly enjoys the challenges of her day-to-day tasks including all aspects of accounts receivable and accounts payable for the Mederi Foundation and Mederi Center.




In Loving Memory of Zeny Yance 

Zeny Yance passed away January 26, 2016 at Rogue Regional Medical Center in Medford, OR at the age of 60. Zeny worked at the Mederi Centre for Natural Healing for more than 20 years, and was devoted to a life of service helping others. She was a great friend to many and always worked with a sense of pride and purpose. Zeny embodies the spirit that the Centre was founded on and her memory will live on with us forever.

© 2022 Mederi Foundation
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