Fleas can cause itchy allergic dermatitis and parasitic disease (red bugs) in cats and dogs. Not only harmful to cats and dogs, but may also harm pets owners. And fleas reproduce at an alarming rate, and once found, they need to be completely eradicated.
The most effective way to prevent fleas is to deworm your pets inside and out!
Monthly drive out. Apply the expelling potion directly to the dog's skin, usually in the stamina area (as shown). External repellents can kill adult fleas parasitic on the dog or bite it, and the effect can last for a month. Some products can also kill eggs, but not all products do. Please check carefully or ask your veterinarian when purchasing.
Monthly internal drive. The veterinarian will prescribe an appropriate dose based on the dog's weight, mixing the tablets into dog food and feeding them once a month. If a female flea bites a dog after taking the preventive medicine, she will ingest a chemical called lufenuron, which is then passed on to the flea eggs, preventing the eggs from hatching (however, lufenuron does not. kills the adults, so it may take a while to work).
Comparison of various types of flea products currently on the market
Lice and Flea Body Wash: Usually contains pyrethrin (a chemical used to kill fleas), which Fleas and ticks on dogs. Wait at least 10 minutes while using, then rinse off with lukewarm water.
Flea Killer Spray: For best results, choose a spray that contains an adulticide and insect growth regulator to ensure that the adult fleas are killed along with their eggs. Do this in a well-ventilated area and be careful not to spray into the dog's eyes. Also wear gloves to protect yourself.

Flea Powder: Usually just a thin layer of powder on the dog's fur will do , does not need to be washed off. Be aware that this powder can make your dog's hair rust to the touch and needs to be replenished from time to time. Start with the dog's head and work your way to the tail, making sure the powder covers the entire body. Don't forget to sprinkle the powder on the dog's bedding, repeat once a week if necessary.
Flea Baths: These products typically contain pyrethrins, permethrin, and organophosphates. The medicated bath requires that the dog be completely immersed in the diluted medicated bath solution, and most products do not need to be washed off.
Flea Control Collars: Flea control collars vary in quality, and many have a limited range of flea control, only killing fleas near the collar (around the dog's head and shoulders). However, a good quality flea collar can still repel or kill fleas when used properly. Some collars are less effective when they get wet.
The lice comb will remove fleas directly from the dog's fur. Comb from top to bottom. When brushing, the brush must touch the dog's skin. If you only brush the dog's hair and ignore the skin, there will still be some fleas left behind.
Immediately after combing, dip the comb in warm soapy water. Soapy water can kill fleas on combs.

Mix equal parts lemon juice and warm water in a shallow bowl. You can also cut a lemon into 4 wedges and put it in boiling water. Soak for 8 hours or overnight, then strain the lemon juice into a bowl. Dip your dog's hairbrush or comb in the lemon juice and brush your dog. After the hair comes into contact with the brush, it is covered with a layer of lemon juice. Be sure to brush your hair thoroughly, re-dipping the brush in the lemon juice every time you brush. Repeat this process 1 time a day for 3 days.
Use lemon juice sparingly to prevent your dog's skin from becoming too dry.

Summary:
In summer, you must pay close attention to your dog's drinking water to prevent dehydration. Drinking plenty of water can also prevent heat stroke, and pay attention to replenishing water and lost electrolytes during exercise.