We now have more information about marijuana than ever, but there are still a bunch of myths that influence the way in which we view the herb.

There are a lot of myths surrounding marijuana, ranging from crazy stuff to others that makes a little bit of sense. This confusion is understandable; it’s only recently that marijuana has earned some legal status across states, and that serious scientific studies are being conducted.

Although much of marijuana’s make up and effect remain mysterious, there’s lots of room to learn more. We scoured the web to find some of the most popular marijuana myths. Here are six of the most common.

According to Ryan Vandrey, a professor from John Hopkins University, THC in cannabis is way higher than it used to be. Since cannabis is now a business, there are expert botanists that breed plants that contain larger quantities of THC. So maybe people smoked more weed in the 70s, but that doesn’t make today’s marijuana any less potent.

There are two major types of marijuana, Indica and Sativa, both of which produce different highs. In short, Sativas are psychoactive while Indicas are more relaxing. It’s a little more complicated than that, since most marijuana plants contain a mix of both, but this generally works as a rule of thumb.

Synthetic marijuana is much stronger than regular marijuana and it can lead to some really awful side effects. Synthetic marijuana has chemicals added in in order to resemble the effect and look of natural marijuana. These chemicals are harmful for your body, with some of the most serious side effects include renal damage, psychosis, cardiovascular harm and changes in the brain.

It’s extremely unlikely to die from a marijuana overdose, but if you smoke too much you can have a pretty awful time. These overdoses can last a couple of hours and include symptoms of anxiety, paranoia, dizziness, and loss of coordination.

While there are tons of products that claim to do this, it’s very, very unlikely and practically impossible to cheat a urine test if there’s marijuana in your system. THC can be detected in urine for up to 10 days after consumption, 30 days if you’re a chronic user. Most products that claim to cheat urine tests simply dilute your urine, which tests can pick up on, flagging your sample as invalid.

Holland, one of the world’s most popular marijuana scenes, has never actually legalized marijuana. In 1978, the government decided not to enforce bans in coffee shops and locales where people get together and smoke/sell small amounts of marijuana. Still, growing, distributing and importing marijuana within the country remains illegal.