Gefitinib 250mg tablet helps to treat non-small cell lung cancer that has spread to other parts of the body. This anti-cancer medicine belongs to the tyrosine-kinase inhibitor group that works by blocking the action of this enzyme that signals the cancer cells to multiply. This medicine can be prescribed alone or in combination with other medicines. Some of the common side effects of this medicine are nausea, vomiting, headache, rashes, diarrhea, weakness, weight loss, etc. However, by following certain precautions, one can reduce the risks of these side effects.