Corn sugar, or corn syrup, is a liquid derivative of corn starch and is used in many foods and drinks to make them sweeter. However, there are a number of substitutes for corn sugar which can be used if it is not available or you prefer to avoid it due to health reasons.
Maple Syrup and Sugar
Made from natural sugars, maple syrup is the syrup form of maple sugar, which is often used as a substitute for corn sugar and syrup. Maple sugars come in cube and candy form and can be eaten straight or added to drinks or food, though the maple sugar taste is very distinct and doesn't blend with certain flavors as well as corn sugar does. However, maple sugars and syrups are healthier and are low in fructose, whereas corn sugars and syrups are high in fructose and can cause you to gain weight, among other health problems, when consumed regularly.
Raw sugar, made from sugarcane, is what common table sugar is made from and can work as a substitute for corn sugar or corn syrup. Raw sugar is much healthier for you then corn sugar or corn syrup, or even the refined table sugar, yet is still considered a high fructose item. However, it's not processed or refined, causing it to break down in whatever you have added it to over time, or not break down enough unless it is cooked or dissolved sufficiently. Raw sugar can be bought at grocery stores in bulk or in individual packet-sized servings.
Your own corn sugar or corn syrup substitutes can be made in your kitchen with the correct ingredients as well. For dark corn syrup substitutes, take 3/4 of a cup of light corn syrup plus 1/4 of a cup of molasses. If you don't have light corn syrup, you can make your own. You'll need a cup of treacle, a cup of liquid glucose, a cup of honey and 200 grams of granulated white sugar, which you should first boil into a syrup in a 1/4 cup of water. Make the light corn syrup first and make enough of it so you can simply add molasses to make the dark corn syrup.