Doctor profile · Federal record

Dr. Katherine Macmillan, M.D.

Gastroenterology Physician (CMS: Gastroenterology) · Internal Medicine Physician · Internal Medicine Physician · Gastroenterology Physician · Simpsonville, SC

  • NPI 1780117416
  • Accepts Medicare
  • 9 yrs in practice
  • Licensed in 3 states
  • Female
  • Group practice
  • No sanctions

Practice & contact

Operates at 3 locations .

NPPES Updated May 11, 2026
Primary practice
741 Se Main St
Simpsonville, SC 296813237
(864) 522-8420
fax (864) 522-8425
Additional location
727 Se Main St Ste 340
Simpsonville, SC 296813249
(864) 455-2888
fax (864) 455-2885
Additional location
13400 E Shea Blvd
Scottsdale, AZ 852595499
(480) 301-8000
Mailing address
300 E McBee Ave Ste 300
Greenville, SC 296012899

Credentials & registration

NPPES · NUCC
NPI registered
April 2017 — 9 yrs on file
Profile last updated
February 23, 2026
Year of graduation
2017 — 9 yrs since
Specialty taxonomy
207RG0100X — NUCC code
State licenses (3)
South Carolina #85580 · Georgia #009641 · Arizona #72379

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1780117416. Last verified May 11, 2026.

Open Payments

Industry payments received

CMS Open Payments
All-time total
$41
Transactions
2
Manufacturers
2
Payer (manufacturer) Industry Txns Amount
Takeda Pharmaceuticals U.S.A., INC. 1 $25.58
Phathom Pharmaceuticals, INC. 1 $15.07

By nature of payment

Food and Beverage
$41

Hospital affiliations

CMS Hospital Compare

Frequently asked questions

Auto-generated from federal data
What is Dr. Katherine Macmillan's medical specialty?
Dr. Katherine Macmillan practices Gastroenterology Physician in Simpsonville, SC.
Where does Dr. Katherine Macmillan practice?
Dr. Katherine Macmillan practices at 741 Se Main St, Simpsonville, SC 296813237. Office phone: 8645228420.
What is Dr. Katherine Macmillan's NPI?
Dr. Katherine Macmillan's National Provider Identifier (NPI) is 1780117416, issued by NPPES.
Does Dr. Katherine Macmillan accept Medicare assignment?
Yes. Dr. Katherine Macmillan accepts Medicare assignment, meaning Medicare-allowed amounts are accepted as full payment for covered services.