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Dr. Leah DeTolla

Leah DeTolla, DVM, grew up in our neighboring town of Westford, Massachusetts. She attended the University of Connecticut and obtained her bachelor’s degree with dual majors in Animal Science and Pathobiology in 2017. She graduated from the Cummings School of Veterinary Medicine at Tufts University in 2021 and received the E. &S. Windsor award for clinical excellence.

She worked for over eight years as a veterinary technician prior to and during veterinary school, and has always been drawn to primary care due to her love for creating lasting relationships with clients and their pets. Her professional interests include dentistry, soft tissue surgery, and clinical pathology.

She is an avid musician and enjoys singing, playing guitar, and listening to music in her free time. She also enjoys hiking, cooking, and cuddling with her rescue cat Remy.

Dr. Kara Grosser


Kara Grosser earned her Doctor of Veterinary Medicine from Cornell University in 2001, then moved to the Boston area to complete a rotating internship in small animal medicine and surgery at Angell Animal Medical Center in 2002.

She focused on emergency medicine and surgery for several years before deciding to focus on day practice. Her interests include preventative care and internal medicine, especially of geriatric patients.

She enjoys spending time with her family, which includes a Siamese cat named Simon, engaging in fair weather outdoor activities, and reading.

Dr. Betty Johnston


Betty Johnston, V.M.D., joined the staff of Acton Animal Hospital in 2005. Dr. Johnston has practiced veterinary medicine for over 30 years, 15 years of which were devoted to the mixed practice of treating large and small animals, and the last 16 years working with small animals exclusively.

She holds a B.S. degree and earned her V.M.D. degree from the University of Pennsylvania. She is a member of the MVMA, the AVMA, and the AAHA.

Dr. Johnston takes a special interest in dog training and participates in obedience, field, rally and agility competitions with her two dogs, Cooper and Gable. The part of veterinary medicine that Dr. Johnston enjoys most is working with owners to get their puppies off to a healthy, happy start with proper medical care and training.

Dr. Daphne Flessas

Veterinarian, Owner

Daphne Flessas, D.V.M., owner of Acton Animal Hospital, is a Massachusetts native who received her Doctorate of Veterinary Medicine from Tufts University School of Veterinary Medicine in 1996. She has practiced in New England for the past 19 years, most recently in Bellingham.

Her veterinary interests include internal medicine, soft tissue surgery, dentistry and dermatology. Dr. Flessas has a passion for education, works with students as much as she can, and is committed to life-long learning in the veterinary field.

She and her husband live in Grafton, MA, and have three daughters. The family shares their home with a French Bulldog named Monkey and a tiny Chihuahua named Pickles, to the utter dismay of cats Ruby, Max, and Trouble.