What is in suprep?

Suprep (the 2.5 L bowel‑prep solution used before colonoscopies) is a polyethylene glycol (PEG) formulation.
Its key ingredients are:

| Ingredient | What it is | Typical concentration in the bottle (per 2.5 L) |
|------------|------------|-----------------------------------------------|
| Polyethylene glycol (PEG) 3350 | A non‑absorbable osmotic laxative that draws water into the colon | ~37 g (≈ 1.5 % w/v) |
| Sodium sulfate | An electrolyte that helps balance fluid shifts | ~12–15 g (≈ 0.5 % w/v) |
| Potassium chloride | Provides potassium to replace what’s lost | ~8–10 g (≈ 0.3 % w/v) |
| Sodium chloride | Adds sodium and chloride to maintain electrolyte balance | ~8–10 g (≈ 0.3 % w/v) |
| Flavoring / sweetener | Usually a mild fruit flavor (often strawberry) and a non‑caloric sweetener (e.g., sucralose) to make the solution more palatable | trace amounts |

The exact numbers can vary slightly by batch, but the composition always centers on PEG 3350 with the listed electrolytes and a small flavoring component.

Bottom line: Suprep is basically a PEG‑3350 solution plus sodium sulfate, potassium chloride, sodium chloride, and a touch of flavoring to make the bowel‑prep drink tolerable.