Christian Aid has launched an emergency appeal as 10 million people face starvation in the east and Horn of Africa.
The food crisis has been brought on by two failed rainy seasons and rising global food prices.
Kenya and Ethiopia are facing particularly severe food shortages.
The food security crisis is so grave that the UN Office for the Coordination of Humanitarian Affairs (UNOCHA) has described it as the worst in the world today. Some places experiencing their driest conditions in 60 years.
Christian Aid emergency teams are in the region and assessing their response.
“The crisis has been building for some time, especially in Kenya and Ethiopia, and is fast escalating across the region,” said Nick Guttmann, Christian Aid’s humanitarian director.
“People are desperate and if we don’t act now we could be looking at one of the worst humanitarian situations the world has seen in a long time.”
Other countries affected by the drought are Djibouti, Somalia and Uganda.
Christian Aid is appealing for funds to implement a raft of life-saving measures across the region.
It plans to provide water to villages experiencing the worst of the drought conditions, and food for families, malnourished children, and pregnant women.
Funds will also go towards animal feed to preserve livestock, as reports describe mortality rates of up to 60 per cent among cattle and sheep in some areas.
UNOCHA warned that thousands of people were being displaced as a result of the food crisis.
Some 15,000 Somalis have poured into Kenya and Ethiopia in search of food.
Elisabeth Byrs, spokeswoman for UNOCHA, said: “While conflict has been a fact of life for them for years, it is the drought that has taken them to breaking point.”
In spite of the need, the UN’s appeal for funds for Djibouti has only reached 30 per cent of the target amount, while appeals for Somalia and Kenya have received around half of the necessary funding.
Byrs said: "If we do not tackle the situation as soon as possible, it could become worse.”