This paper documented several natural products that have antineoplastic activities. Detailed descriptions of the mechanism of action of these products are given. Side effects of these natural products are also described. Based on these side effect profiles and their benefits, these natural products could be used as adjuvant cancer therapies. Traditional anticancer agents usually have debilitating side effects. These natural products would be of great benefit due to their anticancer activities. Additionally, some of these natural products can work proactively in preventing cancer formation with their chemopreventive properties. Incorporation into diet can be recommended after discussion with physician and other health care professionals.