I've been having fun this winter making hats for my church ministry to be distributed at local cancer centers. As a a child I had cancer and experienced 2.5 years of chemo. It was awful when my hair fell out until my gam made me a hat. She made them for every day of the week. They made me feel special. While I made this hat for a pattern I posted on ehow.com out of acrylic, a cotton yarn is a better choice for a chemo cap. Skin during treatment is very sensitive.