Frequencies of drug attributed adverse events
| Placebo (n (%)) | Olsalazine (n (%)) | p Value | |
| Total No patients | 160 | 167 | |
| Patients with at least one related adverse event | 44 (27.5) | 65 (38.9) | 0.035 |
| WHO body system | |||
| Gastrointestinal overall | 27 (16.9) | 54 (32.3) | 0.001 |
| Diarrhoea | 13 (8.1) | 35 (21.0) | 0.001 |
| Nausea | 3 (1.9) | 11 (6.6) | 0.053 |