The Third World is now the West's single most important export market. Its governments are scrimping and saving every penny to import the "best" from the West. More and more evidence suggests, however, that too much of that hard-earned money is being wasted.

It is not just a question of a gold-plated bullet-proof vest, or large quantities of sophisticated arms, or nuclear reprocessing plants or Coca-Coca bottling plants.

It is food and drugs, the essentials of life, that often prey on the do-anything, pay-anything love that uneducated mothers in a desperate environment have for their children. With infantmortality rates that take away before the age of 10 half a mother's children, something "best" from the West is like a pie out of the sky.

One example given in a report, "Insult or Injury," published by the London-based Social Audit, is Brand's Essence of Chicken made by the big British food company Ranks Hovis McDougall. It sells in vast quantities in the Far East, not least to young mothers who have been persuaded by advertising into thinking it is worth eight times the price of a common garden chicken. It is a dark brown, slightly viscous and foaming fluid sold in medicinal portions and labelled as "predigested protein" and "goodness in a digestible form."

A Malaysian consumer group had the essence analyzed. They reported the cost of that protein to be 27 times higher than the cost of protein in eggs and about 130 times the cost of protein in ikan bilis, a common local fish.

Another report recently published by Earthscan, a protege of the United Nations environment program, lists page after page of Western drugs, many of them overpriced and falsely labeled, sold to Third World markets. In India alone, 15,000 branded varieties of drugs are on sales. The Hathi committee in its thorough report on the Indian drug industry concluded that India's health needs could be met by a mere 116 varieties.

In Tanzania, a week's dose of penicillin syrup costs only seven U.S. cents, while one injection of a branded antibiotic costs $21. But in a country where there is one drug salesman for every four doctors, it is no surprise that a large proportion of doctors prescribe the latter. Yet only in life-and-death situations would it be justified.

In Sri Lanka, soluble aspirin produced by a Western drug corporation "elegantly presented and heavily promoted" holds 75 percent of the market. But plain aspirin is in most cases equally good and costs less than a third the price.

Compared with the baby-food business, however, these peccadilloes pale into insignificance. According to James Post, a professor at Boston University, the current world market for infantformula products used in bottle feeding is around $1.5 billion. He estimates that before 1980 the developing world will be spending $1 billion per year on patented substitutes for breast milk. That is more than the World Bank loaned to all the nations of Latin America in 1974.

Nestle, Abbot and Bristol-Myers, whose products include baby food, are all comapnies that at different times in the last four years have come in for a good deal of public attack. Critics have argued that where bottle feeding is introduced in poor communities, infantmortality rates rise substantially.

In Switzerland three years ago, Nestle successfully brought a civil action against a group that had published a pamphlet titled "Nestle kills babies." However, the judge in his summing-up declared, "If Nestle in future wants to be spared th accusation of immoral and unethical conduct, the company will have to change its advertising practice."

In the United States, a Catholic religious order, the Sisters of Precious Blood, sued Bristol-Myers for giving fasle information in a report to share-holders. The two-year case ended at the beginning of 1978 with the court requiring a mailing to be sent to all share-holders containing the company's position and the sisters' critique.

Despite the adverse publicity, there is hard evidence that the baby-food relations campaigns that can have the effect of weaning babies off safe, hygienic, high-protein breast milk onto the vagaries of a powdered product administered through a bottle, often unwashed, overdiluted and used in an environment where infection is all too easy. For that, too often is the way things are in the slums of Bombay, Lagos and Manila.

In the global figures of exports said imports between Third World and the West, the flow of pills and powders makes hardly any dent. But on human lives and loves, it does. Can't we, in the International Year of the Child, do better than this?