Chemotherapy-induced mucositis is a clinically important and sometimes dose-limiting toxicity of cancer treatment, including standard-dose chemotherapy, high-dose chemotherapy and chemoradiotherapy. Consequently, dose reductions or treatment delays resulting from mucositis may impair treatment effectiveness. Symptoms are oral mucositis, dysphagia, abdominal pain and diarrhea, depending on the affected site. Although the underlying pathobiology of oral mucositis has been considerably elucidated over the past decade, there are few interventions for the prevention or treatment validated by randomized trials. The most commonly accepted intervention is basic oral care. Diarrhea is most common in patients treated with irinotecan and in some cases, life-threatening. No definitive interventions for the prevention of diarrhea exist, but there is evidence that loperamide and octreotide are effective for chemotherapy-induced diarrhea. In future, there is a need for well designed trials, preferably including a placebo or no treatment control, validating more effective interventions for managing chemotherapy- induced mucositis.