Tonsillitis is a tonsil infection which is highly discomforting and can be chronic or acute in nature. One of the best natural remedies to treat tonsillitis is the onion juice which provides a great deal of relief from this infection. All you need is an onion and a cup of lukewarm water. Extract fresh onion juice and mix it with lukewarm water. Gargle properly with this mix and repeat 2-3 times a day for best results.