However, recent evidence has shown that dogs, cats, guinea pigs, and other animals should not be given onions in any form, due to toxicity during digestion.[14][15][16] [edit] Medicinal properties and health effects of onionsRaw Onions Nutritional value per 100 g (3.5 oz) Energy 166 kJ (40 kcal) Carbohydrates 9.34 g - Sugars 4.24 g - Dietary fiber 1.7 g Fat 0.1 g - saturated 0.042 g - monounsatura