The tonic water comprises carbonated water, citric acid, sodium citrate (acidity regulator), natural flavourings including quinine, and sweetener (aspartame). These ingredients combine to provide a balanced and refreshing beverage that supports hydration and enjoyment during various occasions. ​

Schweppes Slimline Tonic Water 200ml is free from the 14 major allergens, including gluten, dairy, nuts, soy, and sulphites, making it suitable for individuals with common food allergies. It is also gluten-free, GMO-free, and suitable for vegetarians and vegans. However, it contains aspartame, a source of phenylalanine, which may be unsuitable for individuals with phenylketonuria (PKU). Consumers are advised to check the product label for the most accurate and up-to-date information.