Final answer:
An adverse effect of ephedra is the occurrence of panic attacks. This is due to ephedrine's chemical similarity to adrenaline which can increase anxiety and cause other related side effects.
Step-by-step explanation:
An adverse effect of ephedra includes the occurrence of panic attacks. Ephedra, which contains the active compounds ephedrine and pseudoephedrine, has been used historically as a stimulant and decongestant. Consumption of ephedra can lead to various side effects such as anxiety, sleeping problems, agitation, abnormal heart rhythms, and in some cases, panic attacks. These symptoms are likely because ephedrine is chemically similar to adrenaline, which can increase alertness and energy levels but can also lead to the aforementioned side effects.