Medicines and cosmetics

This page covers one Form 5 content standard from the Consumer and Industrial Chemistry chapter: medicines and cosmetics. The exam expects you to know the main types of medicine with their function and an example, to distinguish traditional from modern medicine, to describe common cosmetics and their possible side effects, and to argue for the correct, safe use of both. Learn the type–function–example pattern, exactly as for food additives.

What a medicine is

A medicine (or drug used therapeutically) is a substance used to prevent, relieve, treat or cure a disease or its symptoms. Medicines act in different ways, so they are grouped by function.

The main types of medicine

• Analgesics (painkillers), relieve pain. Examples: aspirin, paracetamol and, for severe pain, codeine. Aspirin and paracetamol are also antipyretics, meaning they reduce fever.
• Antibiotics, kill bacteria or stop them multiplying, so they treat bacterial infections. Examples: penicillin and streptomycin. Important points: antibiotics do not work against viruses (such as the common cold), and the full course must be completed to avoid antibiotic resistance.
• Psychotherapeutic drugs, act on the nervous system and mental state. They include stimulants (increase alertness), antidepressants (relieve depression) and antipsychotics/sedatives (calm the mind). These are powerful drugs that must be taken only as prescribed.

You should also recognise everyday medicines such as antacids, which neutralise excess acid in the stomach.

Traditional versus modern medicine

• Traditional medicine uses natural materials, mainly from plants and herbs (for example ginger, tongkat ali or herbal tonics). It is often cheaper and long-established but its active dose is less precisely controlled.
• Modern medicine uses synthetic or purified chemicals produced under controlled conditions, so the dose and purity are exact and the drug is tested for safety and effect.

A balanced answer notes that both have value, but modern medicine offers standardised dosage and tested effectiveness.

What cosmetics are

Cosmetics are substances applied to the body to clean, protect, beautify or change its appearance. Common types and their functions include:

• Skin-care cosmetics, moisturisers (keep skin soft) and sunscreens (protect skin from ultraviolet light).
• Hair-care cosmetics, shampoo (cleans hair) and hair dye (colours hair).
• Decorative cosmetics, lipstick, face powder and foundation (improve appearance).
• Fragrances and personal care, perfume (pleasant scent), deodorant (controls body odour) and toothpaste (cleans teeth).

Side effects of cosmetics

Cosmetics can have side effects, and this is commonly examined. Some people suffer skin allergies, irritation or rashes from ingredients or fragrances. Certain skin-whitening products have contained harmful substances such as mercury or hydroquinone, which can damage the skin and health. The exam point is to use cosmetics sensibly, check the ingredients, and choose products approved by the health authorities.

Worked example

Question. A doctor prescribes a liquid paracetamol for a child at a dose of 15 mg per kilogram of body mass for each dose. The child has a body mass of 20 kg. (a) State the type of medicine paracetamol is. (b) Calculate the mass of paracetamol in one dose.

Step 1, Identify the type. Paracetamol is an analgesic (painkiller) and also an antipyretic (it reduces fever).

Step 2, Write the dose relationship. Dose = 15 mg for every 1 kg of body mass.

Step 3, Multiply by the child’s mass. Mass of paracetamol = 15 mg kg−1 × 20 kg = 300 mg.

Answer. (a) Paracetamol is an analgesic/antipyretic. (b) One dose contains 300 mg of paracetamol. This shows why dose is calculated by body mass, too much medicine can be harmful.

Practice question

Question. (a) A patient has a bacterial throat infection. State the type of medicine the doctor should prescribe and name one example. (b) Explain why the patient must finish the whole course even after feeling better. (c) State one possible side effect of using a skin-whitening cosmetic that contains an unsafe ingredient.

Answer. (a) The doctor should prescribe an antibiotic, for example penicillin, because antibiotics kill bacteria or stop them multiplying. (b) If the course is stopped early, the strongest bacteria may survive and multiply again, and repeated misuse leads to antibiotic resistance, so the drug can no longer kill those bacteria; finishing the course clears the infection. (c) It may cause skin irritation, allergy or damage, for example products containing mercury or hydroquinone can harm the skin and health.

Exam tip

Match each medicine to its function: analgesic = relieves pain; antibiotic = kills bacteria; antipyretic = reduces fever; psychotherapeutic = acts on the nervous system; antacid = neutralises stomach acid. Two facts are frequently tested, antibiotics do not work against viruses, and the full course must be completed to slow resistance. For cosmetics, be ready to name a type, a function and a side effect, and always conclude with the theme of correct, safe use rather than condemning medicines or cosmetics outright.

Where this fits

This is content standard 13.5 of the Consumer and Industrial Chemistry chapter. It shares the type–function–example style of the food-additives standard, so revise the two together. Reinforce it with the chapter revision notes and test yourself with the chapter practice questions. In our online 1-to-1 SPM Chemistry lessons, taught in English, from RM50/hr, with a paid one-hour trial, our teachers help you build a compact list of medicine types and cosmetic side effects, because in 4541 these are dependable marks when the classification is precise.

Quick recap

• Medicines prevent, relieve or cure illness; main types: analgesics (pain), antibiotics (bacteria), psychotherapeutic drugs (nervous system); also antipyretics (fever) and antacids (stomach acid).
• Antibiotics do not kill viruses; always complete the course to slow resistance.
• Traditional medicine uses natural/herbal materials; modern medicine uses precise, tested synthetic chemicals.
• Cosmetics clean, protect or beautify the body; they can cause side effects (allergy, irritation) and some contain harmful ingredients, use them sensibly.