Which of the following is a common side effect of chemotherapy?

Nausea and vomiting are well-known common side effects of chemotherapy due to the way these drugs work on rapidly dividing cells in the body, which include not only cancer cells but also healthy cells found in areas such as the gastrointestinal tract. Chemotherapy agents can irritate the stomach lining and influence the brain's vomiting center, leading to these adverse effects. Managing nausea and vomiting is a critical aspect of patient care during chemotherapy, with various supportive medications available to help alleviate these symptoms, thereby improving the overall quality of life for patients undergoing treatment.

In contrast, the other options do not typically align with the common experiences associated with chemotherapy. Hair growth often slows or stops during treatment before regrowing afterward. Enhanced energy levels are not a common side effect, as chemotherapy can lead to fatigue and weakness. Weight gain is also usually not a direct effect of chemotherapy; rather, many patients may experience weight loss due to loss of appetite or the side effects of treatment.