Bone marrow harvesting is a surgical procedure, which is done under anaesthesia (regional or general) in an operation theatre. As the procedure involves inserting a needle into the pelvis bone several times, anaesthesia is given to avoid discomfort to the donor. A special needle (with a syringe attached to it) is inserted into the bone and a small volume of marrow is aspirated. This is done several times. Discomfort/side effects vary from person to person and may include mild pain or soreness at the site, stiffness while walking which may last for a couple of days (rarely a few weeks) and a feeling of weakness/fatigue. There is no long-term effect. The only risk is that of anaesthesia. Most donors are back to work in a few days. The amount of marrow harvested is replaced within a month or so.