The practice of force-feeding prisoners at Guantanamo Bay as a response to the mass hunger strike there has been increasingly criticized. But the military has continued to carry it out. Now, Al Jazeera has revealed in detail how the practice is takes place–and it’s not pretty.

Al Jazeera’s Jason Leopold obtained a document revealing how force-feeding works at Guantanamo. The Standard Operating Procedure for force-feeding was formulated by United States Southern Command, the military branch that oversees operation of the prison.

Here’s 6 revelations from the force-feeding document and Leopold’s article.

1. Masked and Shackled

The document states that prisoners who are force-fed are restrained by being shackled to a chair. Prisoners are also required to wear masks over their mouths to “prevent spitting and biting.” In some cases, Guantanamo prisoners are shackled for two hours. The masking and shackling of the prisoners is done to facilitate the tube that is snaked through prisoners’ nostrils until an X-ray or test dose of water confirms that the nutritional supplement reached their stomach.

Though the military claims that the size of the tube they use–3.3 milimeters–doesn’t cause problems, a detainee told a different story. Through his federal defender, Kuwaiti detainee Fayiz al-Kandari said that the tube used on him is too big and painful. His defender told Al Jazeera that “It takes several attempts to get the tube into the right place. Once it goes down his throat he has a difficult time breathing. There's a gag reflex.”

2. No Vomiting Allowed

Once the forced feeding process is over, a prisoner is placed in a cell that does not have running water. A guard then observes the prisoner to make sure he does not vomit up the nutritional supplement that was forced inside him.

If the prisoner does vomit, he is punished. “Participation in the dry cell will be revoked and he will remain in the restraint chair for the entire observation time period during subsequent feedings,” the document reads.

3. Isolation as Punishment for Hunger Striking

The Southern Command policy also outlines why prisoners are being isolated from one another: to break the hunger strike. “In the event of a mass hunger strike, isolating hunger striking patients from each other is vital to prevent them from achieving solidarity,” the military document states.

Indeed, this is exactly what has happened in the midst of the current hunger strike. On April 13, military guards staged a raid at Guantanamo’s communal camp and threw over 100 prisoners into single cells. So far, though, the isolation policy has not worked.

4. Doctors Work Hand in Hand With Military

The medical staff at Guantanamo does not make independent decisions as to how to handle hunger-strikers. Instead, they follow what the military says. The document reveals that the military has final say over who is force-fed, and that “doctors and nurses, who conduct the feeds, are on hand simply to carry out the military's policy,” as Leopold writes.

“It is a very frightening idea that the medical staff is an adjunct of the security force,” said Leonard Rubenstein of the Center for Public Health and Human Rights at Johns Hopkins. “The clinical judgment of a doctor or a nurse is basically trumped by this policy and protocol. Doctors are not acting with the kind of professional medical independence [they should]. It's clear that, notwithstanding references to preservation of detainee health in the policy, the first interest is in ending the protests.”

5. Drugs Used

Over-the-counter medication and other drugs are used on prisoners to facilitate the force-feeding process. One of the drugs used is Phenergan, which is used to treat nausea, vomiting, pain and could also be used as a sleep aid, Leopold writes. The other drug is “Reglan, which is used to treat heartburn caused by acid reflux. Long-term use of Reglan has been known to cause the irreversible neurological disorder, tardive dyskinesia,” according to Leopold.

6. No Consent Needed

The American Medical Association (AMA) has criticized the fact that prisoners’ consent is not taken into account. “Every competent patient has the right to refuse medical intervention, including life-sustaining interventions,” a recent AMA letter sent to the Pentagon states.

But the military’s policy, as stated in the document, is that consent is not needed. Medical personnel are supposed to make an effort to obtain consent to force-feed a prisoner. But the document states that if there is no agreement from the Guantanamo prisoner, “medical procedures that are indicated to preserve health and life shall be implemented without consent from the detainee.”