Tongkat ali or longjack herb is a tree native to Southeast Asian countries, including Malaysia, Thailand and Indonesia. It is sold as an herbal supplement throughout the world. Proponents of the plant believe that it boosts testosterone levels. Male users of tongkat ali often take supplements to increase their bodybuilding abilities or to alleviate sexual problems. Some research has shown that the plant has anti-cancer properties. Natives of Southeast Asia use the plant as an aphrodisiac.

Cancer Risks

Tongkat ali increases testosterone levels in the user. This can aggravate and complicate the conditions of users with certain types of cancer and other ailments. Prostate cancer, breast cancer, liver disease, heart disease, kidney disease, diabetes and sleep apnea are all health problems that using tongkat ali can exacerbate by taking tongkat ali. Using herbal supplements of this plant can hinder treatment of and recovery from these diseases. Tongkat ali may also weaken immune systems already compromised by disease.

Psychological Effects

Ray Sahelian, a medical doctor specializing in natural supplements, reports that there have been some psychological effects among longjack herb users. These side effects include restlessness, anxiety and insomnia. Prolonged experiences with these problems can deteriorate a person's health and well-being. Insomnia prevents sufferers from getting adequate sleep. Extended periods of sleeplessness have lowered libido. Anyone taking tongkat ali supplements for their sexual health need to take a low daily dose to avoid any negative impacts resulting from periods of insomnia the herb causes.

Increased Aggression

Users take longjack herb to increase testosterone levels. Higher levels of testosterone may increase aggression. Some users may become more impatient and easily angered because of their unusually heightened testosterone levels. Avoid taking high dosages of the herb to avoid any aggressive episodes. Be mindful of the changes in your body's chemistry in order to anticipate and navigate through any negative mood swings.

Increased Body Temperature

Some users of tongkat ali extract have reported an increase in their body's temperature after they started taking the supplements. This can make a person especially uncomfortable in warmer climates or on hot days. Users may also experience facial flushing associated with their raised temperature. These side effects may subside after a few weeks of continued use. Refraining from taking high dosages of the supplement may also help to avoid or alleviate increased body temperature.