Eric Chak, MD
Gastroenterology · Davis, CANPI 1225271331
Payments from drug & device makers
What this record shows
This record is dominated by speaking fees: $1,225 of the $1,631 with a category attached, or 75.1%. Salix Pharmaceuticals, A Division Of Bausch Health US, LLC accounts for 75.1% of it on its own, with 7 other manufacturers making up the rest. Reporting peaked in 2019 at $1,240 and has fallen 71.6% since, to $352 in 2025. That places this record below the midpoint for gastroenterology clinicians in CA, where the typical reported total is $1,790.
Across 19 payments — averaging $85.83 each. Meals, travel, consulting and speaking fees, gifts and royalties reported by drug and device makers.
- Salix Pharmaceuticals, A Division Of Bausch Health US, LLC$1K
- Johnson & Johnson$113
- Madrigal Pharmaceuticals$88
- AbbVie$76
- Gilead$55
- Takeda Pharmaceuticals U.S.A., Inc.$40
- plus $35 from 2 others
Across 153 payments — averaging $5304.97 each. Payments tied to a research study. These frequently flow through the physician to a hospital or research institution rather than to the physician personally.
- GSK$631K
- Gilead$138K
- Bausch Health US, LLC$43K
What the payments were for
- Speaking & faculty fees$1,22575%
- Food & beverage$40625%
General payments by program year
Who reported the general payments
Companies are grouped under their corporate parent — a single manufacturer often files under several CMS reporting entities. Research and ownership payments are counted separately and are not in this table.
| Company | Payments | Total |
|---|---|---|
| Salix Pharmaceuticals, A Division Of Bausch Health US, LLC | 1 | $1,225 |
| Johnson & Johnson | 5 | $113 |
| Madrigal Pharmaceuticals | 3 | $88 |
| AbbVie | 3 | $76 |
| Gilead | 3 | $55 |
| Takeda Pharmaceuticals U.S.A., Inc. | 2 | $40 |
| Ardelyx, Inc. | 1 | $18 |
| Celltrion USA Inc. | 1 | $17 |
What the payments were tied to
Products named in the reported payments. Only payments of $100 or more are attributed here — the typical reported payment nationally is a meal worth about $16, and listing those product-by-product would be noise.
- XIFAXAN$2,450
How this compares
$1,631 in reported general payments places this provider in the 45th percentile of 1,885 gastroenterology providers in California.
Medicare billing
What this is not: this is the amount Original Medicare Part B allowed for services this provider billed in 2024. It is not their income. It excludes Medicare Advantage — now more than half of all Medicare enrollment — along with Medicaid and all commercial insurance, and it is gross practice revenue before staff, rent, supplies and malpractice premiums. CMS also suppresses any figure covering ten or fewer patients, so low-volume providers appear smaller than they are.
Most prescribed under Part D
| Drug | Claims | Cost to plans & patients |
|---|---|---|
| VemlidyTenofovir Alafenamide | 98 | $166,921 |
| XifaxanRifaximin | 32 | $95,792 |
| Entecavir | 46 | $12,398 |
| Ursodiol | 21 | $2,786 |
| Pantoprazole Sodium | 39 | $582 |
| Gavilyte-GPeg3350/Sod Sulf,bicarb,cl/Kcl | 34 | $564 |
| Spironolactone | 31 | $555 |
| Azathioprine | 12 | $501 |
| Peg-3350 And ElectrolytesPeg3350/Sod Sulf,bicarb,cl/Kcl | 26 | $388 |
| CholestyramineCholestyramine (With Sugar) | 11 | $274 |
| Ciprofloxacin Hcl | 12 | $237 |
| Gavilyte-CPeg3350/Sod Sulf,bicarb,cl/Kcl | 13 | $224 |
| Omeprazole | 13 | $213 |
| Trazodone Hcl | 18 | $145 |
| Furosemide | 14 | $58 |
Paid to pharmacies, not to this prescriber.
Companies that both paid and supply prescribed drugs
These companies both reported payments to this provider and make drugs the provider prescribed under Medicare Part D in 2024. For most specialties this overlap is expected — a cardiologist who is paid by a cardiology drugmaker also treats heart disease. It is shown so the reader can see it, not because it implies anything on its own.
| Company | Paid to this provider | Part D cost of their drugs |
|---|---|---|
| GileadVemlidy | $55 | $166,92198 claims |
| Salix Pharmaceuticals, A Division Of Bausch Health US, LLCXifaxan | $1,225 | $95,79232 claims |
Reading this fairly. The Part D column is what drug plans and patients paid pharmacies — this provider received none of it, and it reflects how many patients they treat and what those drugs cost. Against peers, this provider's reported payments sit in the 45th percentile of 1,885 gastroenterology providers in California.
Other gastroenterology in Davis
- Bennett RothLos Angeles$2.8M
- Douglas NguyenMission Viejo$2M
- Sammy SaabLos Angeles$1.9M
- Kenneth ChangNewport Beach$1.3M
- Joo HwangStanford$1M
- Drew SchembreWalnut Creek$659K
- Quan Nhula Jolla$641K
- Sadeea AbbasiLos Angeles$556K
- Ali RezaieWest Hollywood$519K
- Kenneth BinmoellerSan Francisco$507K
Where these figures come from
- Payments: CMS Open Payments, program years 2019–2025 (publication P06302026_06032026).
- Billing: Medicare Physician & Other Practitioners, data year 2024. Original Medicare Part B only.
- Identity: NPPES NPI Registry, July 2026.