Pyrotherapy is a way of treating illnesses by using heat. It's like when you get a fever when you're sick - your body gets really warm to try and get rid of the bad germies.
Doctors use different methods to apply heat to the body, like hot water or steam, hot rocks, or even fire! They put the heat on specific parts of the body where the illness is, like your tummy or your joints.
The heat helps your body kill the bad germs and viruses that are making you sick. It can also help your body get better by increasing blood flow and making your muscles relax.
Pyrotherapy can be really helpful for some illnesses, but it's important that a doctor does it and not to try it at home by yourself.