It depends on what type of pill. Possible side effects of the combined pill include weight gain, high blood pressure, blood clots and loss of sexual desire. The mini pill (with progesterone only) has fewer side effects and gives more or less the same level of protection. However, many people have no side effects at all, and even within the two types, there are different brands, so sometimes switching brands eliminates any side effects. It's worth remembering that although the pill may not be for everyone, millions of women all over the world take it with no problems at all.