Just as the internet transformed how we buy books and clothing, it has also given drug dealers an easy and sometimes even legal way to connect with eager buyers.

“We have learned that illicit drug suppliers are not the glamorous mafia leaders that we typically see in such movies as ‘Goodfellas’ but rather an infinite number of runner boys that emerge from every crack in the sidewalk,” wrote forensic psychiatrist Dr. Carolina Klein in a 2011 article in the Journal of the American Academy of Psychiatry and the Law. “Now, however, the pipeline opens up inside each individual’s home.”

Like other internet-based businesses, online sellers of drugs offer convenience and access to a global marketplace.

Complicating the efforts of cities and countries to plug this pipeline, many of these chemicals are not illegal or they fall into murky legal zones.

To skirt existing laws and import regulations, sellers market these products, labeled as “legal highs” or “herbal highs,” on websites, drug-related discussion boards, and in email blasts

For some people, buying online from the comfort of their home takes some of the darkened alley feel out of a drug transaction.

However, it doesn’t eliminate the risks.

Read More: Prescription Drugs Are Leading to Heroin Addictions »

International Drug E-Commerce

Last year, a 17-year-old Minnesota high school senior died after taking a synthetic psychedelic drug from China that he bought online.

Authorities suspect that the drug was dipropyltryptamine, a hallucinogenic known online as “DTP.”

They also believe it was sold for “antioxidant testing use,” allowing it to be imported into the country.

Drug suppliers also use other labels to avoid detection, such as “not for human consumption” or “for research purposes only.”

China has garnered a lot of attention recently as the go-to place for illegal, or legal, but dangerous, drugs.

Many of these drugs enter the U.S. through postal agencies and shipping companies.

The Minnesota teen bought the drugs for personal use. However, some people buy these drugs online in bulk for resale on the street.

A few years ago, the Maine Drug Enforcement Agency seized 24.5 pounds of “bath salts” that arrived from China.

In Bangor, Maine, the drugs were sold on the street for $150 per gram. The total street value of the seized drugs was more than $1.7 million.

The drugs were also linked to at least five deaths in that city during a two-year period.

Some officials say that China is a major source of these drugs because of a lack of laws against making bath salts and other psychoactive substances.

A New York Times report last year found that Chinese companies were also selling other drugs including the dangerous stimulant known as “flakka” and a synthetic marijuana known as “spice” or “K2.”

One Chinese e-commerce portal sold spice alongside trampolines and air conditioners.

In 2010, 11,406 visits to emergency rooms were associated with the use of “spice.” One third of these visits involved adolescents and young adults.

This was followed by another wave of ER visits in 2015.

Read More: Synthetic Marijuana Poisoning »

Online Drugs Closer to Home

Not all of the drugs sold online come from China. Some are made much closer to home.

These include “cutting agents” that are added to cocaine or other illegal drugs. By selling less-than-pure drugs, dealers can make a lot more money.

Common cutting agents include benzocaine, lidocaine, paracetamol, and caffeine.

Benzocaine, sold as a powder, is an antiseptic used to numb tooth pain. That numbing is similar to the effect that cocaine has on the nose.

Benzocaine can be mixed with cocaine in a 50-50 ratio without a noticeable difference in drug quality, making it the cutting agent of choice for many drug dealers.

One of the U.K.’s biggest suppliers of cutting agents was recently convicted of conspiracy to supply controlled drugs.

According to the Daily Mail, before his arrest, 26-year-old Gregory King sold 50 kilograms of benzocaine in one day — twice as much as pharmaceutical company Glaxo Smith Klein sold globally in 2015.

King made the benzocaine and other cutting agents in his own workshop. He sold enough to make $127 million worth of cocaine.

Benzocaine is also available online for legal purchase, in much smaller amounts, from major online retailers.

Some people may also smoke or snort benzocaine by itself trying to replicate a cocaine high.

However, benzocaine is far from a safer high. Because its effects are much weaker, people may use it in higher doses, which can lead to a fast or slow heartbeat, stopped breathing, or seizures.

Other legal highs carry health risks, including excited or paranoid states, coma, and seizures.

The U.S. has banned many chemicals that have effects similar to those of illegal drugs. But people keep creating new chemicals in order to evade laws or provide “better” highs.

In Europe, authorities are monitoring more than 450 legal highs, according to a report by the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA).

Many of these are available online.

“I am particularly concerned that the internet is increasingly becoming a new source of supply, for both controlled and uncontrolled psychoactive substances,” Dimitris Avramopoulos, European commissioner for Migration, Home Affairs, and Citizenship, said in a press release last year in response to the report.

Read More: Many Older Americans Are Taking Dangerous Drug Combinations »