Fennel seeds may be able to effectively treat body odour. Fennel can reduce bad breath and body odour that originates in the intestines. Eat whole fennel seeds after every meal whenever needed. You may also drink a cup of fennel tea each day to help reduce body odour. Make fennel tea by crushing 2 to 3 teaspoons of fennel seeds and then simmering the crushed seeds in 1 cup of water for 15 minutes.