Complex sentence: Garlic oil is produced and used for cooking and seasoning purposes and as a nutritional supplement, and is sometimes purveyed in the form of capsules, which may be diluted with other ingredients.
Split into simpler sentences: Garlic oil is produced and used for cooking and seasoning purposes. It is used as as a nutritional supplement, and is sometimes purveyed in the form of capsules, which may be diluted with other ingredients.