What type of cells tend to be damaged the most during chemotherapy?

Cancer cells: Chemotherapy is designed to kill cancer cells, which is does quite well. There is some effect on normal cells(blood cells) yet it is much less than to cancer cells and it is temporary effect on blood cells which recover in 3-4 weeks time.. They are back to normal.

Fast growing cells: Most chemotherapy affects fast growing cells. These will include the cancer cells you are trying to kill, but unfortunately chemo also affects hair cells, cells of the gastrointestinal tract and the bone marrow (makes red and white blood cells, platelets). These give the known side effects of chemo. Luckily the body can recover using stem cells that aren't as sensitive to chemo.