[4] Common side effects include abdominal pain, vomiting, diarrhea, weakness, and rashes.

[7] Capecitabine is indicated for Adverse effects by frequency:[9][10][11][12] Notes on adverse effects: Contraindications include:[11] In 2020, the EU and UK license was updated to state that capecitabine was contra-indicated in patients that "have a known complete absence of dihydropyrimidine dehydrogenase (DPD) activity".

[14] In US, as of 2024, there is no specific contraindication on the package inserts however, there is a cautionary warning: "Patients with certain homozygous or compound heterozygous variants in the DPYD gene are at increased risk for acute early-onset toxicity and serious, including fatal, adverse reactions due to XELODA (e.g., mucositis, diarrhea, neutropenia, and neurotoxicity).

XELODA is not recommended for use in patients known to have certain homozygous or compound heterozygous DPYD variants that result in complete absence of DPD activity.

No XELODA dose has been proven safe in patients with complete absence of DPD activity.