The first thing you must consider when you ask "Can tonsils cause bad breath?" is whether or not your tonsils are inflamed and you are ill. If you are ill, and your tonsils are working to help your immune system, there is a chance that the smell is coming from them. However, once your illness is resolved, the smell should go away. If you have tonsillitis, it is quite possible that the source of your bad breath is coming from them. If you have had tonsillitis quite often, you may need to consider having them removed in order to get rid of the source of your bad breath.
Unfortunately, any imbalance within your digestive system can be a source of bad breath, which can confuse the answer of your question of "Can tonsils cause bad breath?". When you are trying to find the source of your problem, you must make certain that you are taking the time to consider all of the potential culprits for bad breath. Brushing at least two times a day with a long life toothbrush, or a simple dietary change or vitamin supplement may be the answer to your problems. If you take the time to review all aspects of your problem, you should be able to find the solution.