The 5th Amendment states that "No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation"
This is important as it means that, amongst other things, the Government can't make you provide testimony against yourself.
For instance, in Rochin v. California, the Supreme Court held that cops couldn't beat you until you vomited up the drugs you swallowed to hide from the cops. They ruled that the police officers violated the suspect's 5th amendment rights.
