By the BBC's Ishbel Matheson Nairobi

Thirty-four-year-old Susan sits in the crowded, waiting room of Mbagathi hospital, in Nairobi, feeling nauseous.

Like two million Kenyans, she is HIV-positive.

Unlike others, Susan is lucky enough to be able to afford powerful anti-aids drugs.

If we have generics at a fair price, then the majority of these people will be able to see their next birthday or see their children finish school

Dr John Wasonga, Kenyan doctor

The side-effects make her feel sick, but the medicine keeps her alive.

"Before I started on these drugs, I honestly thought I was dying. Now I'm OK. I can work".

A single mother with two young children, it is a struggle to find the $85 each month for the treatment.

Most Kenyans cannot even dream of paying this fee.

The cost of these vital drugs in Africa has become a rallying point for campaigners, across the continent and internationally.

Non-branded drugs

In Kenya, that pressure has resulted in a new law which came into effect on 1 May.

Its aim is to remove barriers to cheaper anti-retrovirals.

Under the new law, non-branded drugs known as generics, can be imported or manufactured in Kenya.

Cheaper branded medicines can also be imported from abroad.

The hope is that greater competition will lead to a price drop.

Dr John Wasonga treats many HIV-positive patients at Mbagathi.

"Generic compeition is the way forward.

"If we have generics at a fair price, then the majority of these people will be able to see their next birthday.

Kenya hosts an increasing number of Aids oprhans

"Or see their children finish school. That's the reality of it."

Kenyan manufacturers are poised to take advantage of the new, freer market.

At Cosmos pharmecutical company, researchers have been working for a year and a half, to produce their version of established triple therapy drugs.

The samples are ready - the white pill boxes are sitting in the director's office.

But the company will have to wait at least six months for the drugs to be licensed.

Many campaigners believe the law is only the first step.

Kenya's state bureaucracy is still painfully slow.

'People are dying'

Cosmos's director, Prakash Patel, wants to see a fast-track licensing process for essential medicines.

"People are dying all the time.

"We should be able to give them some hope by giving these drugs as soon as possible."

But big, multi-national companies claim that, even under the new law, the impact will be marginal.

The marketing director of Glaxo SmithKline in Kenya, Dr William Kiarie, points out that the price of his company's anti-retrovirals has dropped dramatically in the past two years.

A course of anti-retrovirals is now one tenth of its original price. However, the usage has not grown by the same proportion.

People are dying all the time... We should be able to give them some hope by giving these drugs as soon as possible

Prakash Patel, Cosmos director

Only about 3,000 Kenyans are believed to be on triple-therapy.

"Bringing the price down by 10%, 20%, we are going to see very little increase in people using the drugs," says Dr Kiarie.

"Basically, because people are poor and governments are poor."

Like other African countries, the Kenyan Government does not have enough money in the coffers to provide these drugs free to its people.

It is not just the cost of the medicine.

The health service is ramshackle, and to administer this complex treatment would require a major investment in doctors, equipment and training.

Aids crisis

However, Sophie-Marie Scouflaire of the charity Medicins Sans Frontiers, argues that cheaper drugs will create a snowball effect.

Charities running mission hospitals will be able to afford them. More and more middle-class Kenyans will have access.

And the private sector will pay.

"If the medicines are cheaper, you will have more private companies who will give them to their staff, " says Scoulfaire

Even under the new law, most Kenyan Aids sufferers will not be able to afford generic drugs

"It will be less expensive to treat their employees (with anti-retrovirals), than pay bills from hospitals."

Removing legal barriers is likely to help.

But the dilemma of how to get these medicines to the masses remains.

Rich nations are reluctant to provide all the funds needed by African governments - and the Kenyan Government is often accused of not taking the Aids crisis seriously enough.

Caught in the middle, is a generation of Kenyans who will continue to die early, without any hope of treatment.