They can cause seizures, comas and even death – but you can buy them online, at gas stations or even in certain stores. We’re talking about “legal highs.”

You can smoke them, or swallow them. Toxicologist Richard Clark says the new ways to abuse drugs are all legal.

“Some people call these legal highs,” Richard Clark, MD, Director of Toxicology, UC San Diego Health System, told Ivanhoe.

“Bath salts” are synthetic drugs made in underground labs and marketed as household items. Last year, close to 1,000 people reported exposure to poison control centers.

“The patients we saw with ‘bath salts’ had significantly more violence, and significantly more self-harm behavior,” Dr. Clark said.

Synthetic marijuana is another designer drug made by spraying natural herbs with synthetic chemicals to mimic the effects of marijuana. But, it’s very potent and dangerous. In 2010, more than 11,000 ER visits were associated with its use.

“What we end up seeing with people with this new synthetic marijuana is violence, and an occasional convulsion,” Dr. Clark said.

You use them when you’re sick, but some are taking cough syrup to get high. One study found one in 10 American teens abused products with DXM, an ingredient found in these meds. However, at high doses the drug can cause vomiting, impaired vision, memory loss and even a coma.

Another legal drug being abused is Benadryl.

“People have Benadryl parties in lots of places in the United States,” Dr. Clark explained.

The antihistamine can spark hallucinations in high doses and too much could also cause seizures and death. The bottom line when it comes to legal highs?

“They could kill themselves,” Dr. Clark said.

Lawmakers have tried to make some of the ingredients in many of these drugs illegal. In fact — President Obama signed a federal law to ban “bath salts.” However, experts say many of the makers and manufacturers have found ways to slightly alter the chemical makeup of their products – so they remain legal highs.