We went to Siem Reap last January and took the necessary medication for malaria. My doctor actually prescribed doxycycline for me to take for 28 days while my travel companion was prescribed malarone for 7 days. I just finished taking the tablets just recently and I would just like to say that the medicines didn't have any of the horrible side effects on neither of us while we were in Cambodia or even after we returned home. Nothing whatsoever. No severe diarrhea, no sunburn, none of the sort.
Some of the messages I read here made the medicines appear to be absolutely horrible and even risky for one's health. I do feel better having taken the medicines as I was bitten by some mosquitoes not in the temples but right in my hotel room, a four star one at that.
I especially felt a lot better I took the medicine after I met a female tourist on the flight home who was bitten by a mosquito while in Siem Reap. The swelling on her arm was so bad and itchy she said she was going straight to her doctor as soon as she got back to her country.
To be fair I do not intend to scare anyone intending to travel to Cambodia. I was forewarned of the mosquitoes in that country and frankly I didn't see a lot of them. In fact, I was not bitten not even once during the three days I wandered in the temples of Angkor. I enjoyed my stay and plan to return for a longer stay sometime soon.
I simply wish to inform people that the anti-malarial medicines mentioned above are not as horrible as some people make them appear to be.