The usual sensible health precautions for life in the tropics
apply to Malaysia: apply sunscreen regularly and generously, avoid
excessive sun and drink lots of water to replace lost fluids in the
humid climate (tap water is potable in KL, but bottled water is
recommended everywhere else).
There are no reported malarial outbreaks in Malaysia, but Dengue
Fever sometimes appears. Prevention is much better than cure with
mosquito-borne diseases, so applying strong insect repellent
(especially in the jungle) and wearing clothing that covers your
ankles and the back of the neck and knees at dawn/dusk is
recommended.
Heat rash and 'traveller's tummy' from the spicy cuisine are the
two most common issues for tourists, so carrying an antihistamine
cream and digestive aids are advised to overcome these minor
discomforts.
Jellyfish can be a problem in the waters around Penang, so a
rash vest is recommended when swimming.
The standard of medical care and facilities in Malaysia is very
good, including several teaching hospitals in KL with Australian
affiliations.