A mule or courier is someone who smuggles something across a border (as opposed to sending by mail, etc.) for a smuggling organization. The organizers employ mules to reduce the risk of getting caught themselves. Methods of smuggling include hiding the goods in a vehicle, luggage or clothes, strapping them to one's body, or using the body as a container. Sometimes the goods are hidden in the bag or vehicle of an innocent person, who does not know about this, for the purpose of retrieving the goods elsewhere.
In the case of transporting illegal drugs, the term drug mule applies. Slang terms include Kinder Surprise and Easter Egg. This is often done using a mule's gastrointestinal tract or other body cavities as containers. One method involves swallowing latex balloons (often condoms or fingers of latex gloves) or special pellets[clarification needed] filled with the goods and recovering them from the feces later. Other methods of carrying drugs within the body include insertion of the package directly into the anus or vagina. This method is far more vulnerable to body cavity searches. Another method is called Body Packing, which means the drugs are attached to the outside of the body, using tape or glue. Packed between the cheeks of your bottom or rolls of fat. Other inconspicuous places, like the bottom of special cut out shoes, inside belts, or the rim of a hat, were used more often prior to the early 90's. Due to increased airport security the "body packing" method is rarely used anymore.
The practice of transporting goods outside the body is called body packing; this is done by a person usually called a mule, or bait. This method is, in general, rarely used today. However, some narcotics-trafficking organizations such as the Mexican Cartels will purposely send 1 or 2 people with drugs on the outside of their body to purposely be caught, so that the authorities are occupied while dozens of mules pass by undetected with drugs inside their body. But even these diversion tactics are becoming less and less prevalent as airport security increases.
A swallower typically fills tiny balloons, often made with multilayered condoms or more sophisticated hollow pellets, with small quantities of a drug, usually heroin or cocaine. These balloons may be swallowed or may be hidden in other natural or artificial body cavities as the rectum, a colostomy, or vagina.
The swallower then attempts to cross international borders, excrete the balloons, and then sell the drugs for profit. It is far more common for the swallower to be making the trip on behalf of a drug lord or drug dealer. Swallowers are often impoverished and agree to transport the drugs in exchange for money or other favors. In fewer cases, the drug dealers can attempt extortion against people by threatening physical harm against friends or family, but the more common practice is for swallowers to willingly accept the job in exchange for big payoffs. An increasingly popular type of swallowing involves having the drug in the form of liquid-filled balloons or condoms/packages. These are impossible to detect unless the airport has high-sensitivity X-Ray equipment. Most of the major airports in Europe, Canada, and the US have these machines. Note that a liquid mixture of water and the drug will most likely not be detected using a standard X-Ray Machine. As reported in Lost Rights by James Bovard: "Nigerian drug lords have employed an army of 'swallowers', those who will swallow as many as 150 balloons and smuggle drugs into the United States. Given the per capita yearly income of Nigeria is $2,100, Nigerians can collect as much as $15,000 per trip."
The U.S. Supreme Court dealt with body packing in United States v. Montoya De Hernandez. In Hernandez, a woman attempted to smuggle 88 balloons of cocaine in her gastrointestinal tract. She had been detained for over 16 hours by customs inspectors before she finally passed some of the balloons. She was being held because her abdomen was noticeably swollen (she claimed to be pregnant), and a search of her body had revealed that she was wearing two pairs of elastic underpants and had lined her crotch area with paper towels. This is done because balloon swallowing makes bowel movements difficult to control. The woman claimed her fourth amendment rights had been violated, but the court found in favor of the border authorities.
With regard to traffic from South America to the US, the US Drug Enforcement Administration reports: "Unlike cocaine, heroin is often smuggled by people who swallow large numbers of small capsules (50–90), allowing them to transport up to 1.5 kilograms of heroin per courier."
In all, around 18% of the UK's female jail population are foreigners, 60% of which are serving sentences for drug-related offences–most of them drug mules.
The Bali Nine are an example of a drug-smuggling ring.
Detection and medical treatment
Routine detection of the smuggled packets is extremely difficult, and many cases come to light because a packet has ruptured or because of intestinal obstruction. Unruptured packets may sometimes be detected by rectal or vaginal examination, but the only reliable way is by X-ray of the abdomen. Hashish appears denser than stool, cocaine is approximately the same density as stool, while heroin looks like air.
In most cases, it is only necessary to wait for the packets to pass normally, but if a packet ruptures or if there is intestinal obstruction, then it may be necessary to operate and remove the packets surgically. Oil-based laxatives should never be used, as they can weaken the latex of condoms and cause packets to rupture. Emetics like syrup of ipecac, enemas, and endoscopic retrieval all carry a risk of packet rupture and should not be used. Repeat imaging is only necessary if the mule does not know the packet count.
Ruptured packets often require treatment as for a drug overdose and may require admission to an intensive care unit. Body packers are not always reliable sources of information about the contents of the packages (either because of fears about information being passed on to law enforcement agencies or because the mule genuinely does not know) and urine toxicology may be necessary to determine what drugs are being carried and what antidotes are needed 
- Drug Enforcement Administration
- Illegal drug trade in Colombia
- Money mule
- U.S. Immigration and Customs Enforcement (ICE)
- United States Border Patrol
- War on Drugs
- Low, VHS; Dillon, EK (October 2005). "Agony of the ecstasy: Report of five cases of MDMA smuggling". Australasian Radiol 49 (5): 400–3. doi:10.1111/j.1440-1673.2005.01503.x.
- Walter BM et al. "A curious case of bodypacking". Forensic Toxicology 2012, DOI: 10.1007/s11419-012-0139-4;.
- Bovard, James Lost Rights, the Destruction of American Liberty, 1995.
- News from DEA, Congressional Testimony, 11/09/05
- "Jamaica's women drug mules fill UK jails". BBC News. 2003-09-13. Retrieved 2010-05-13.
- "Nigerian drug mules 'on the rise'". BBC News. 2005-10-03. Retrieved 2010-05-13.
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- 2006 news item on swallowers
- Khan FH (2005). "The cocaine 'body-packer' syndrome: Diagnosis and treatment". Indian Journal of Medical Sciences 59 (10): 457–8. doi:10.4103/0019-5359.17054. PMID 16272682.
- Fatal Heroin Intoxication in Body Packers in Northern Thailand during the Last Decade: Two Case Reports
- Child body packing
- Radiology Teaching Case — Cocaine Overdose from Body Packing
- http://www.springerlink.com/content/p734317724gn7022/ Forensic Toxicology 2012, DOI: 10.1007/s11419-012-0139-4; A curious case of bodypacking; Walter BM et al.