The most common side effects with Vectibix (seen in more than 1 patient in 10) are rash, erythema (redness of the skin), skin exfoliation (skin flaking), pruritus (itching), dry skin, skin fissures (cracks in the skin), paronychia (nail bed infection), diarrhoea, fatigue (tiredness), nausea (feeling sick), vomiting, dyspnoea (difficulty breathing) and cough.