Bought both the 200ml and 100ml, but being a nice taste syrup it disappears fast, so would recommend the larger quantity, but the 100ml would be good for issues when returning back to work, or having to travel while not feeling 100%. Back this up with the lozenges and it makes the flu/cold and feeling ill that little bit easier on you. Also easy on the gut and didn't cause heartburn like other brands. Recommend.