According to my information:

The tops of the branches may be picked and dried at any time as long as the plant is not denuded or the branches cut back past the viable buds. Place stems in a brown paper bag and keep in a hot place, either in the sun or near a heater, until dry.

Warning: Avoid when pregnant or breast-feeding. Excessive doses can be fatal. Less severe effects include high blood pressure, racing of the heart, confusion, nervous stupor, twitching and convulsions, anxiety, insomnia, vomiting, urinary problems. Avoid if suffering from high blood pressure, insomnia, diabetes, thyroid problems, prostate problems, depression, hyperthyroidism or glaucoma, or if taking monoamine oxidase inhibitors. Prolonged usage (less than 3 months) may lead to addiction. Use with caution if driving or operating machinery. Do not take Ephedra with other stimulants, including caffeine. Never administer to children under the age of 18. Keep out of reach of children.

I have a feeling you might be confusing Ephedra with Horsetail, the stems of which can be poisonous. It is advised that children, who are particularly vulnerable, do not touch the stems of Horsetail.

I would advise that you don't use this plant at all until you have 100% certainty of its identity and safety.