There are 2 simple things you can do to avoid being bitten by mosquitos.
1 - to ensure that if you've had your windows, doors, curtains open in the daytime - You DON'T switch on any lights until you have closed some of the openings and tightly shut the curtains. Then you won't attract the mosquitos into the room.

2.. 7-10days Before you go away, buy & start taking One Vitamin B1 strength 100 mcg, am & pm, ie twice daily, to create a build-up in your blood.
Everyday that you are away, & for a few days after you return - ensure that you take them once or twice daily - depending upon the quantity of bites on other people.
The reason being that mosquitos dont like the smell/taste of you when you've been taking the Vit B1.

I know it works well as I took it daily in China in August. I got 2 bites the first day as I hadnt begun taking it quite early enough before & that was it... But the rest of the group all got badly bitten every day & night. - and I gave them all my sprays.
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Cynthia Lewis, London.,, England UK

Citronella oil works very well. You only need a few drops rubbed into exposed areas. It's also much cheaper than fancy branded sprays or aerosols.

Mike Anderson, Kuwait,

I always take Brewer's Yeast a few days before I go away and throughout my holidays to Spain and haven't been bitten by a mosquito in five years!

Berenice Moran, Dublin, Ireland