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About

Granite State Gastroenterology is a New Hampshire-based GI clinic offering general gastrointestinal care, inflammatory bowel disease (IBD) management, esophageal motility disorders, liver disease treatment, and hepatitis C care. Headquartered in Derry with five office locations across NH (including Derry, Raymond, Windham, and Bedford). Key personnel include Gastroenterologist Managing Partner Dr. Leon McLean and Director of Operations Jennifer Marshall. They emphasize patient choice and communication, with a small team (about 13 employees). Priorities likely include IBD care, GI disorders, and liver disease, supported by a regional presence and multiple contact numbers for scheduling. If you’re seeking GI services in Manchester, note that Granite State Gastroenterology operates offices within NH communities and may serve nearby areas; for Manchester-specific GI care, confirm closest location and available IBD or liver disease specialists.

Clinic Type

Gastroenterology

Address

Bedford, NH; Londonderry, NH; Windham, NH

Phone

603-432-8802

Email

Opening Hours

Not published — contact the clinic to confirm hours.

Services Offered

  • general gastrointestinal disorders
  • inflammatory bowel disease
  • esophageal motility disorders
  • liver disease
  • treating Hepatitis C
  • gastroesophageal reflux treatments
  • colonoscopy
  • polyp removal
  • treatment of rectal bleeding
  • upper endoscopy
  • capsule endoscopy
  • gastrostomy tube (PEG) placement
  • acid reflux evaluations
  • liver disease management
  • irritable bowel syndrome
  • pancreas disorders
  • anal and rectal disease

Technology & Equipment

  • endoscopy
  • gastroscopy
  • capsule endoscopy
  • colonoscopy
  • PEG tube placement
  • acid reflux testing

Team

  • Granite State Gastroenterology team, Board Certified in Gastroenterology; four physicians; three Advanced Practice Practitioners (APPs); two Physician Assistants; one Nurse Practitioner — physicians & APPs

Insurance & Payment

Languages Spoken

  • English

FAQs

What services does Granite State Gastroenterology offer?

Gastrointestinal care including evaluation and treatment of GI disorders, colonoscopies, upper endoscopy, PEG tube placement, liver disease care, irritable bowel syndrome, inflammatory bowel disease, esophageal disorders, hepatitis C, pancreatic disorders, and rectal diseases.

Social Media

Photos

What Patients Say

Overall sentiment across review platforms: positive

  • Birdeye/Google aggregate: 5.0 out of 5 stars (aggregated based on 73 reviews across platforms) (73)
  • WebMD Care: 4.5 out of 5 stars (23 ratings (8 written reviews))

Patients praise

  • Staff described as welcoming, friendly, and helpful
  • Providers praised for being thorough, knowledgeable, and genuinely listening to patient concerns
  • Positive experiences with long-term management of chronic conditions like Crohn's disease
  • Clean and professional office environment

Common complaints

  • Concerns expressed regarding the knowledge level of some Physician Assistants (PAs) compared to doctors

"DR. Dainiak is the absolute rock star of Gastroentetology... he listens , i mean really listens. i’m happy to report that my crohn’s is under control."

WebMD Care review

"Dr. Horton is an excellent and thorough doctor! She listens to your questions. She answers any and all questions or concerns you may have and provides explanations and advice should you seek those too."

Granite State Gastroenterology website

"Dr. Dainiak is very nice. Unfortunately, the PA they feed me to knows almost nothing, which is concerning regarding my care."

Yelp review

Synthesized from public review platforms as of Jul 11, 2026 — sources: [1][2][3][4].

Information sourced from the clinic's website as of July 11, 2026.

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