Cocaine, methamphetamine, and heroin generate headlines when it comes to drug use. But in recent years, legal substances have done considerably more damage. Overdose deaths in the United States caused by prescription painkillers, for example, now exceed deaths caused by cocaine and heroin combined. At least those painkillers require a doctor’s note. As Demi Moore’s recent hospitalization for alleged use of nitrous oxide suggests, there is a reason why a growing number of over-the-counter, legal, and quasi-legal substances have public health and law-enforcement officials alarmed. Here are seven of the most dangerous legal drugs. Forget a relaxing time in the tub with this drug: the effects of “Bath Salts” resemble those of cocaine and methamphetamines. In 2011, the DEA banned Mephedrone, the active compound in most brands of bath salts, but enterprising merchants have simply altered the formula. Paul J. Richards, AFP / Getty Images Smoking dried salvia, an herb grown in Mexico and Central America, produces hallucinations and “psychedelic-like changes in visual perception, mood and body sensations,” much as LSD does. An important difference: the high from salvia lasts no more than 30 minutes. Carlos Osorio The warning labels say “Not For Human Consumption,” but that hasn’t deterred customers from seeking synthetic alternatives to marijuana such as “Spice” and “K2.” As with bath salts, the DEA has banned the active ingredients, but manufacturers have tweaked the ingredients to evade law enforcement. Douglas R. Clifford, St. Petersburg Times / Zuma We’re not talking about using NyQuil as directed: cough syrup containing Dextromethorphan (DXM), when taken in large quantities, produces euphoria, slurred speech, and dizziness, according to the National Institute on Drug Abuse. It is especially dangerous when combined with alcohol. Some brands that contain DXM: Robitussin and Coricidin. Photodisc / Getty Images Amyl nitrate and butyl nitrate have been used medically to alleviate chest pain, but they’re thought of as sexual enhancers, and are available without prescription under names such as Rush and Bang!!. It’s not just for refilling whipped cream dispensers: nitrous oxide, which is sold in tiny metal cylinders, is the same gas dentists use during procedures. It’s popular with teenagers, and is allegedly the substance that led to Demi Moore being hospitalized. Jvoves / Flickr Inhaling the fumes of paint thinner, gasoline, or glue can produce dizziness and hallucinations, but also brain damage, depression, and even death by overdose. Getty Images