just looked this up for you Sarah hope it helps this is ingredients for mcd's milkshakes dont think there is anything in there that should harm.
Milkshakes
Milkshake Base
Milk, Sugar, Whey Powder, Glucose Syrup, Cream,
(40% Butterfat), Stabiliser (E412 Guar Gum, E407
Carageenan (Standardised with Sugars)), Dextrose,
E410 Locust Bean Gum.
Banana Flavour Milkshake Syrup
Sugar, Water, Glucose Syrup, Natural Colouring
Agent (E100 Curcumin), Banana Flavour, Natural
Colouring Agent (E160c Paprika Extract), Acidifier
(E330 Citric Acid), Preservative (E202 Potassium
Sorbate).
Chocolate Flavour Milkshake Syrup
Glucose Syrup, Water, Glucose-Fructose Syrup,
Reduced Fat Cocoa Powder (6.6%), Acidulant
(E338 Phosphoric Acid), Colour (E150 Caramel),
Caramel Sugar Syrup, Salt, Flavour, Butter
Fat, Cocoa Mass, Acidulant (E330 Citric Acid),
Emulsifier (E322 Soya Lecithin), Preservative (E202
Potassium Sorbate).
Strawberry Flavour Milkshake Syrup
Water, Sugar, Glucose Syrup, Strawberry Juice
Concentrate, Colour (E162 Beetroot Juice
Concentrate), Acidulant (E330 Citric Acid),
Strawberry Flavour, Preservative (E202 Potassium
Sorbate).
Vanilla Flavour Milkshake Syrup
Water, Sugar, Caramelised Sugar, Colour (E150d
Caramel), Flavour (Vanillin), Acidifier (E330 Citric
Acid), Preservative (E202 Potassium Sorbate