Chun Ouyang, M.D., PH.D.
NPI 1336115328 · Internal Medicine Physician · Walnut Creek, CA
Enrolled with Medicare as Practitioner - Gastroenterology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Chun Ouyang, M.D., PH.D. is a Internal Medicine Physician provider in Walnut Creek, CA (NPI 1336115328).
Provider details
- NPI number
- 1336115328
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D., PH.D.
- Sex
- Male
- Sole proprietor
- No
- License
- 217077 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
20 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 23 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Peg3350/Sod Sulf,bicarb,cl/Kclbrand: Gavilyte-C | 335 | 328 |
| Cholestyramine (with Sugar)brand: Cholestyramine | 48 | 11 |
| Omeprazole | 47 | 21 |
| Mesalamine | 41 | 15 |
| Entecavir | 37 | 11 |
| Pantoprazole Sodium | 34 | 15 |
| Lactulose | 30 | — |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$22 across 1 record (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-02-28
- Last updated
- 2021-12-13
Frequently asked questions
- What is Chun Ouyang's NPI number?
- Chun Ouyang's National Provider Identifier (NPI) is 1336115328, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Chun Ouyang's specialty?
- Chun Ouyang is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Chun Ouyang located?
- Chun Ouyang's practice location on file with NPPES is 1425 S Main St, Walnut Creek, CA 94596-5318.
- What is Chun Ouyang's phone number?
- The practice phone number listed in the NPPES registry for Chun Ouyang is (925) 295-4020.
- Does Chun Ouyang accept Medicare?
- Chun Ouyang is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Chun Ouyang's NPI active?
- Yes — Chun Ouyang's NPI (1336115328) is active in the NPPES registry as of the last update on 2021-12-13.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.