Try fasting, such as water fasting, juice fasting, fruit fasting, or just abstaining from food. eating healthier will naturally make you smell better and bad smells usually go away after a period of time. However during fasting and detoxification, bad smells, like bad breath will arise, they are normal and they will pass. You must just power through such phases, after a few days your body will have detoxified itself and will smell much better.
Always mind your diet. avoid dairy products such as cow milk, cheese etc
eat your veggies and fruits, spinach, kale lettuce carrots, such a diet change will aid in your IBS bowl problems and help your general health issues you may be having.
Try drinking prune juice as a laxative to clean out your body.