Q: SOMETIMES when I travel on a business trip, I am pressured by my overseas colleagues to enjoy the company of a lady for hire. I am very health conscious and as I do see other girlfriends in Hong Kong I try to be very careful about transmitting any diseases which could cause health problems. My friends tell me that the ladies for hire now carry medical certificates which state that they are free from contagious and sexually transmitted diseases. Should I trust these certificates? Can I rest assured that the health risk is minimal if I have sex in a commercial sex establishment with a woman who is medically certified? Dr Rose writes: I would not personally trust any medical certificates offered by any commercial sex establishments. Such certificates only indicate the woman's health status at the time she was examined. If she has been exposed to a sexually transmitted disease, such as herpes, she would not develop any symptoms until seven to 10 days after exposure. If the examination was done prior to the 10-day period, the test would not detect the disease. Because the average prostitute services as many as 30 clients a day, it is highly probable that immediately after she has been given a clean bill of health, she goes on to have sex with another client and exposes herself to many sources of potential infection. Don't take any chances. Any contact with a prostitute places you at high risk of contracting a sexually transmitted disease including gonorrhea, syphilis, herpes, chlamydia, hepatitis and AIDS. If you do decide to have sex with a prostitute, take precautions and make sure you wear a condom. Also, remember that oral sex can also transmit some diseases and is not 100 per cent safe. Q. I notice that one of my friend's children stutters occasionally. He is four years old. Is it due to stress and poor self-esteem? Is it something that he can control? His parents think he will outgrow the problem and have not sought professional help. Dr Rose writes: Stuttering, which occurs in about one per cent of the general population, is a speech disorder in which the speaker repeatedly hesitates and delays uttering words. Temporary stuttering in young children between the ages of two and four is fairly common and is not necessarily related to stress and poor self-esteem. In fact, the latest studies show that stuttering is more likely to be physiologically based and not related to an inferiority complex. Some researchers believe it may be related to how the brain processes language. Instead of using the left side of the brain, the stuttering child processes language with the right side of the brain. Stuttering is more common in boys, twins and people who are left-handed. Stuttering is also related to the speed of speech. Speech therapy is focused on getting the child to slow down the speed of his speech. Although the majority of children outgrow the problem when they get older, your friends may wish to take their son for a professional assessment so that early speech therapy can be prescribed if necessary. Q. I recently heard about a special Chinese herb that is good for treating malaria. I know there have been more problems with drug resistance to the different strains of malaria in Southeast Asia. What is the herb and how does it work? Dr Rose writes: The Chinese herb to which you are referring is qinghaosu or artemisinin, derived from the sweat worm-wood plant qingrhao. It has been used for centuries to treat hemorrhoids and fevers. In 1971, Chinese scientists found that qinghaosu was effective in treating malaria when given orally or by suppository. Since then, it has been used to treat more than a million cases of malaria. Preliminary studies, with small numbers of people, indicate that qinghao can cure malaria much more quickly than other anti-malarial drugs and that it does not appear to have any toxic effects. The drug appears to be preferable to quinine, which is commonly used to treat malaria, because it is safe, speedy and easy to administer. However, because the results of these studies are still preliminary, they are being viewed with caution. So far there have been no major efforts to revamp existing anti-malarial treatment programmes. Dr Rose Ong is a certified family physician licensed in the United States. She welcomes enquiries but cannot answer them individually. Specific questions should be addressed to your own physician. Additional enquiries: Peak Corporate Health Management, 525-6600, fax 525-8100.