Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.

Dr. Mark M Allendorph, MD

Individual provider Gastroenterology Physician · NPI 1922094002

Dr. Mark M Allendorph, MD is a Gastroenterology Physician in Alton, Illinois. Practices as a sole proprietor. Licensed in Illinois.

Licensed in
IL
In the registry since
2005
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

See every abbreviation used in this directory →

Practice location Address checks out

2 Memorial Dr Ste 205
Alton, IL 62002-6723
Phone: (618) 465-5849
Fax: (618) 465-5853
Show map & directions

Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Gastroenterology Physician (primary) Taxonomy 207RG0100X · Licence 036072597 (IL)

Record details

NPI number1922094002
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorYes
NPI enumeratedSeptember 23, 2005
Last updated in NPPESMay 27, 2008
Mailing address2 Memorial Dr, Suite 205, Alton, IL 62002-6723

Other providers in Alton