Accepted answer
Start with the three inputs: fibre grams, fluid volume and physical activity. Most cases resolve on the first two.
Red flags that change this from a management question to a clinical one: no bowel movement for several days with abdominal distension and vomiting, blood in the stool, or unexplained weight loss beyond what is expected.
Gastrointestinal adverse events, indicative pooled rates
| Event | Active arm | Placebo arm | Timing |
|---|
| Nausea | 40–45 % | 15–20 % | Peaks 1–2 wk after each step |
| Vomiting | 15–25 % | 5–8 % | Follows nausea |
| Diarrhoea | 20–30 % | 10–15 % | Early, variable |
| Constipation | 20–25 % | 8–12 % | Later onset, persistent |
| Discontinuation for GI events | 4–7 % | 1–2 % | Mostly during escalation |
Ranges span agents and doses; read the specific prescribing information for a specific figure.
Physical activity has a modest but real effect on transit time and is free, which makes it worth including even though it will not fix this on its own.
The fibre-and-fluid relationship in functional constipation is established across intervention studies, and fibre without adequate fluid worsens symptoms.
Nothing here is medical advice.
Osmotic first, stimulant reluctantly, and not as a standing arrangement.