Background Extravasation of some cytotoxic drugs can cause pain, erythema, inflammation and tissue damage. There are proven procedures for managing extravasation of older cytotoxic drugs, such as doxorubicin. However, there are limited data for the newer cytotoxic drugs, such as cetuximab. Aim To describe a case of suspected cetuximab extravasation. Clinical details The IV cannula of a 75‐year‐old male receiving cetuximab was partially dislodged. The patient reported pain and swelling at the administration site. It was established that approximately 1 mL of drug solution (equivalent to cetuximab 5 mg) had leaked into the perivascular tissue. Attempts to aspirate the leaked drug from the perivascular tissue was unsuccessful. Pain and swelling resolved within 30 minutes of the incident. Subsequent reviews confirmed no adverse effects at the extravasation site. Outcomes No discernible amount of cetuximab could be aspirated, which suggests that the perivascular tissue was exposed to the drug without significant adverse effects. The short duration of reported pain and minimal adverse effects suggest cetuximab is not a vesicant or irritant. Conclusion This case of suspected cetuximab extravasation resulted in a rapid resolution of symptoms, suggesting cetuximab is a neutral drug and not a vesicant or irritant.