Hi,
My fiance and I are going to be spending 3 months travelling around Thailand, Cambodia, Laos and Vietnam. We have been told to use a repellent with DEET in it. I have seen some on the web for 50% and 100% can anyone advise which should be used?
Thanks 
These threads may help...
http://www.travellerspoint.com/forum.cfm?thread=12773
http://www.travellerspoint.com/forum.cfm?thread=12502
http://www.travellerspoint.com/forum.cfm?thread=12382
The higher the better.. nothing worse than mozzie bites, let alone what they may carry!
Not to be alarmist, but a friend of mine told me that he heard recently that there is a carcinogenic ingredient in DEET. 
I havent come across anything else saying that though.
50% Deet should be sufficient. The 100% stuff is horrible and feels awful on your skin.
Once I'd ran out of Deet spray in Asia I just used to use whatever I could find in local shops. I found the citrus based sprays to be quite effective actually and much nicer to use.
Quoting samsara2
Not to be alarmist, but a friend of mine told me that he heard recently that there is a carcinogenic ingredient in DEET.
I havent come across anything else saying that though.
I have seen studies on DEET...it is dangerous to use on young children in the very concentrated strengths...since they don't know better than to stick their hands in their mouth after rubbing their arms...etc...And for occational use..it doesn't post a risk. Mind you, I would be slathering it on 10 times a day, 365 days a year 
dammit...I wouldn't be slathering it on!!!!
I want an edit button!!! 
Forget the repellent! Apparently GIN and Tonic keeps mozzies away best!
Well, actually its the tonic! But hey, it'll taste m uch nicer if you have gin in with it too!
50% DEET is strong enough....Go for the stuff in a roll-on its easy to apply without making too much mess and less likely to leak.
Its easiest to find the 20% stuff in shops, and that worked for me too, although maybe it depends what time you're there.... I was there in the dry season so there'll have been fewer mozzies.
I'm sure its true that DEET is really bad for you, but then malaria can't be much fun either. Three months isn't so long. When I was there I only really put it on in the evenings.
I've heard burning mosquito coils works really well too, but obviously not when you are walking about.
Yuck.
I just got back from my RTW trip and as i get bitten really badly, to the point ive ended up in hospital twice with them.....so i was prepared with my 100% deet before i went....however i kept getting bitten, my theory is that it actually attracts them....also a few people i met had the same theory!!!It was a no go for me, i find superdrugs own brand more effective, its pretty good!!!however after one too many horrendous its i went to this teeny tiny pharmacy who reccomened lemon grass oil!!!!she gave me this water spray thing with lemon grass oil in and it was perfect, never got bitten once!!!!!!I thought it was fantastic!!!!