When I add one item with a quantity of let's say 3 to the cart using
exp:cartthrob:add_to_cart_form
and then show the content of the cart using
{exp:cartthrob:cart_items_info}
I get 3 rows with the same item.
Is there a way to tell Cartthrob to aggregate the items and show one row with the quantity=3?
PS: The items do have individual item options. I was wondering if this is the reason CT displays them on separated rows.
You'll want to adjust these options on the Products screen in the CartThrob module settings:
Though if they do indeed have individual item options which could be different for each line item, it could be that CT overrides these settings. Try it out.
Also, for future reference, I'd suggest asking ExpressionEngine-related questions on the ExpressionEngine Answers SE site.