Answer
The gastrointestinal side effects listed as very common with valganciclovir are diarrhoea, nausea, vomiting and abdominal pain.
Sources for this answer
- Valganciclovir 450 mg film-coated tabletsAurobindo Pharma - Milpharm Ltd. · emc · SmPC §4.8 Undesirable effects · Version 5Document updated
Sources checked