Homemade Onion Cough Syrup – Grandma’s Secret Recipe

A bad cough or sore throat can be one of the worst feelings in the world. But if you’ve got an onion and some sugar on hand, you can make a cough remedy that soothes the throat but tastes great, too! It’s perfect for adults and kids, alike, and it is simple to make with ingredients you probably have in your kitchen right now.

If you are like me and every other mama of littles, you’ve probably had your fair share of sick kids. One of the very worst feelings is when your sweet child has a bad cough. Usually a cough is nothing major, but try telling yourself that when you hear them hacking their lungs up all night, and you can’t give them anything other than cuddles and love! Flu and cold season are the worst!

I’ve begged the doctors for cough medicine (they won’t even recommend ANYTHING), and I’ve tried some of the “herbal” concoctions on the market for little ones, but they just didn’t work. And when my little boy Dexter recently ended up with a fever of 105 and a bad cough, I took matters into my own hands with this homemade cough syrup recipe.

Now, please PLEASE remember that any fevers need to be treated separately from a cough. Dexter had an infection that required antibiotics, and we gave him Children’s Tylenol for the pain, fever and discomfort. Doctors will be able to advise you on the best course of action. BUT – I’ve not had a doctor yet who would suggest anything for a cough. 

While I’m not normally one for home remedies or alternative medicine, I do find that this specific recipe really does work. I looked up the science behind it and even spoke to my doctor to find out why.

It turns out that onions are active against some microbes, including Staphylococcus, Streptococcus, Klebsiella, Pseudomonas and Candida. These are pathogens commonly found in the throat or pharynx and often associated with sore throats or infections that cause cough.

In fact, another great common household ingredient that does the same thing is raw honey. Unfortunately, honey is not to be given to children under a year of age, so I use sugar in this recipe to make it useful to everyone. If you have older children, though, or you are making it for yourself, stay tuned to the end of the post for an alternative version that features garlic and honey instead!

This is a super simple recipe. Simply start with an onion and some regular granulated sugar. I use Vidalia Onions, as they are naturally sweeter, and I think they appeal to kids more. You can use any type of onion you want, though some will have a stronger flavor.

First, peel the onion so that all of the outer skin is removed. It doesn’t have to be perfect – you won’t be eating it! Then, slice it up into disks.

Next, take a bowl and lay a slice of onion in the bottom. Sprinkle it with sugar, liberally. I use about a teaspoon per slice.

Stack another slice of onion, and sprinkle with sugar. Continue layering onions and sugar until you have filled the bowl.

Then, cover the bowl tightly. I use a strong Tupperware bowl with a lid to make sure it doesn’t leak. Leave it out for an hour or two, allowing the sugar to draw out the liquid within the onions. It is this liquid that will become the cough syrup.

You can use the syrup right away, and it is safe to use as often as needed. After it has juiced a bit, it is best to put it in the fridge, where it can stay for up to two days safely. Of course, because of his bad cough, ours was gone in 24 hours. But since it takes no time at all to make another batch, it’s no problem!

For an alternative version, take an entire bulb of garlic and smash it to separate the cloves.

Remove the skins, and place them into a small bowl or container. You can choose to mince them first to start the juicing process, or even roughly chop them up with your knife, but I tend to just throw them into the bowl whole. The flavor is VERY strong and spicy, so the more you chop them, the stronger the flavor.

Now pour on some raw honey, preferably local, onto the garlic. Use enough to almost cover the garlic. You can also use the regular old honey in a teddy bear if it’s all you have, but raw honey is better, and local honey will help with local allergens.

Just like with the onion and sugar, you’ll want to cover with a lid and leave for a couple of hours, letting the natural juices in the garlic combine with the honey to form a syrup. It’ll have a thinner consistency than normal honey, and the flavor is MUCH spicier. I would not suggest giving this to kids.

I am not the biggest fan of the garlic syrup plain, but added into some lemon ginger tea, it really helps to soothe the throat and relieve a cough. I also know several men who mix a bit of whiskey with it for their own form of self-medication.

Whichever way you choose to go, homemade cough syrup can be a great way to get through flu season.

The flavor was a big hit with my kid, and it TRULY helped his cough. It didn’t take it away by any means, but it gave him instant relief that lasted for about two hours at a time. As soon as he started to cough, he’d look up at me and say, “Mommy, I need more medicine.”

The greatest part is that you can give them more than one “dose” at a time. It won’t hurt them because it’s natural. The only warning I would give is that because it is very sugary, you’ll want to make sure  they rinse their mouth or brush their teeth so that the sugar doesn’t do any damage.

I even made this for Daniel when he was still a baby, and it worked just as well for him. Use a small medicine syringe for easy dosing.

What are YOUR favorite home remedies?

Katie Reed

Katie Reed is a passionate writer and mother of four vivacious boys from Salt Lake City, Utah. Drawing from her own journey through TTC, pregnancy, and the joys of raising children, she offers a wealth of insight into the world of motherhood. Beyond her heartfelt tales, Katie delights her readers with family-friendly recipes, engaging crafts, and a curated library of printables for both kids and adults. When she’s not penning her experiences, you’ll find her crafting memories with her husband and sons—Dexter, Daniel, Chester, and Wilder.