Huperzine A should be avoided by children, pregnant women and nursing mothers.

Because of possible adverse effects in those with seizure disorders, cardiac arrhythmias and asthma, those with these disorders should avoid Huperzine A. Those with irritable bowel disease, inflammatory bowel disease and malabsorption syndromes should avoid Huperzine A.

Because Huperzine A may increase the likelihood of seizures for individuals with epilepsy, it should not be taken by individuals who have or have had seizures.

Huperzine A may cause the heart to beat slower than it would normally. Individuals who have heart rhythm abnormalities should avoid taking Huperzine A due to the chance it may cause dangerous disruptions in heart rhythm.

A side effect of increased acetylcholine activity is an increase in body secretions, including mucus and saliva. This effect may worsen respiratory conditions such as asthma, bronchitis, and emphysema. Individuals with chronic respiratory conditions should not take Huperzine A.

Increased production of stomach acid, possibly caused by huperzine A's cholinergic effect, may aggravate ulcers of the stomach or small intestine. Therefore, individuals with ulcers should avoid taking huperzine A.

Urine output may also be increased by Huperzine A. Individuals who have bladder conditions or other conditions, such as benign prostate hyperplasia (BPH), that may be made worse by increased amounts of urine should not take Huperzine A.