In prisons, despite strict security measures and supervision, prisoners may still obtain drugs through various channels. Here are some common ways： 1. **Brought in by external personnel**： -**Visitors**: Family members, friends or other visitors of prisoners may secretly bring drugs in during visits. This may be achieved by hiding in small objects, clothing, or the body. -**Prison staff**: Sometimes, prison staff may be bribed or coerced to assist in bringing drugs into the prison. 2. **Internal transactions**： -**Transactions between prisoners**: Some prisoners may obtain drugs through internal networks, usually through transactions or exchanges with other prisoners. -**Black market inside prisons**: There may be an underground economy in prisons, and drugs are part of it. Prisoners may obtain drugs through the black market. 3. **Mail or parcel**： -**Disguised mailing**: Drugs may enter prisons by mailing packages, usually by pretending to be legal items, such as books, food, or other daily necessities. -**Drone delivery**: In recent years, drones have been used to deliver drugs and other contraband to prisons. 4. **Other ways**： -**Medical system**: Some prisoners may obtain drugs through abuse or illegal access to prescription drugs. -**Activities outside the prison**: When prisoners carry out work or activities outside the prison, they may have the opportunity to obtain drugs and bring them back to the prison. Prison management departments usually take a variety of measures to prevent the flow of drugs, including strict searches, surveillance, drug testing, and supervision of staff. However, the drug problem remains an ongoing challenge in prisons.