When you combine two everyday household items that seem completely unrelated, the result can be surprisingly effective. Garlic is a common kitchen ingredient known for enhancing the flavor of dishes, and it also carries many health benefits. Dishwashing liquid, on the other hand, is essential in every kitchen for breaking down grease, removing stains, and keeping dishes clean and shiny. But what happens when you soak garlic in dishwashing liquid?

The answer is unexpected: it becomes a powerful cockroach repellent and killer. Cockroaches are known for their rapid reproduction. If not controlled promptly, they can multiply quickly and cause hygiene issues. Anything cockroaches touch often carries a foul odor, and getting rid of that smell is extremely difficult. Even worse, cockroaches can carry over 40 types of bacteria, which can contaminate food and potentially affect your health.

Many people rely on chemical insecticides to eliminate cockroaches. Although effective, frequent use of these chemicals may negatively impact human health. That is why a simple homemade mixture—garlic soaked in dishwashing liquid—can be a much safer alternative.

How to Make the Garlic–Dish Soap Solution

First, slice fresh garlic into thin pieces. Add an appropriate amount of dishwashing liquid and water into the bowl of garlic. Stir well, then let the mixture sit for about 30 minutes so that the scent of garlic blends with the dish soap.

After soaking, strain out the liquid and pour it into a spray bottle. Spray this solution onto areas where cockroaches often appear such as bathrooms, kitchens, corners, or under cabinets. Over time, you will notice that the number of cockroaches decreases significantly.

Why This Mixture Works

Cockroaches are attracted to the scent of dishwashing liquid but are strongly repelled by garlic. When they smell the dish soap, they approach and ingest the liquid mixture—accidentally swallowing garlic in the process. Garlic irritates their digestive system, causing them to slowly die.

Additionally, dish soap contains surfactants that interfere with water molecules and compromise the cockroach’s respiratory system. Because cockroaches breathe through tiny openings on their abdomen, coming into contact with soapy liquid can clog these respiratory pores, causing them to suffocate.

Alternatively, you can crush garlic, mix it with water, and spray it directly in cockroach-prone areas. This method won’t kill them instantly but is highly effective in repelling them and preventing them from entering your home.

Other Safe and Effective Ways to Repel or Kill Cockroaches

1. Citrus Peels (Orange, Lemon, Grapefruit)

Citrus peels not only leave a refreshing scent around the house but also naturally repel cockroaches. You can dry the peels and place them in areas where cockroaches often appear. Another method is to mix fresh lemon juice with water and spray it around corners and crevices where insects hide. The strong citrus scent discourages cockroaches from approaching.

2. Alum (Phèn Chua)

The distinctive smell of alum drives cockroaches away. Dissolve alum in warm water and use the mixture to mop your floors. Once the floor dries, alum seeps into cracks and leaves behind an odor that cockroaches cannot tolerate. After a short period, you’ll notice they disappear from your living space.

3. Bay Leaves

Bay leaves are commonly used in cooking, but their mild fragrance is highly unpleasant to cockroaches. You can place whole dried bay leaves in cupboards, wall cracks, or under appliances. For a stronger effect, grind dried bay leaves into a fine powder and sprinkle it in problem areas.

4. Onions

Onions have a pungent smell that cockroaches hate. Simply slice an onion and place the pieces in areas where cockroaches frequent. The scent will force them to stay away. However, replace the onion slices regularly to maintain effectiveness.

5. Laundry Detergent

Cockroaches are attracted to sugar, so this method works especially well. Dissolve laundry detergent in water and add a small amount of sugar. Place the mixture in shallow containers where cockroaches often pass by. Once they drink the sweetened solution, the detergent will cover their respiratory openings and kill them gradually.

6. Beer Traps

Cockroaches are surprisingly drawn to the aroma of beer. You can use leftover beer to create a simple trap. Pour beer into an empty can, cut off the top, and place it where cockroaches gather. After a few nights, you’ll find many cockroaches drowned inside the can.