Severe food and clean water shortages were brought on by the worst drought to hit the region in 60 years.
An appeal last year by Scottish Catholic relief charity SCIAF raised over £1.1 million.
The money has gone towards providing emergency aid to communities in Ethiopia, Kenya, South Sudan, Somalia and Eritrea.
The aid included food and water rations, as well as cash payments for the most vulnerable including pregnant women, the elderly and malnourished children under five.
Cash and food for work schemes were set up in Ethiopia and Kenya to allow able-bodied members of the community to access food and money to buy essentials such as medicine.
Saku Dambala is an elderly woman living in the Miyo district of the Borena region in southern Ethiopia. She received cash to buy food.
“All my livestock is dead but we are alive because of the support we are getting from this project although most of the people are malnourished," she said.
"There are many people like that in this area. Without your support I would be in trouble.”
The work included clearing grassland of invasive plants to allow additional grazing space, and rehabilitating ponds to hold more water and help stave off future droughts.
When conditions improved, SCIAF gave cattle to people who had lost livestock.
To help make communities more resilient in the future, the charity dug new wells, constructed sand dams, provided water filters, and distributed fertilisers and drought resistant seeds.
Lorraine Currie, SCIAF’s Head of International Programmes, said its supporters had saved many thousands of lives.
“SCIAF supporters really pulled out all the stops and donated a staggering £1.1 million to last year’s Horn and east of Africa drought appeal," she said.
"This money and the emergency support it provided saved the lives of thousands of people.
“Whilst the drought has now passed and the acute need of the people has dropped, SCIAF is continuing to work with its partners and local communities to increase their resilience against future droughts by distributing drought resistant seeds and rehabilitating community resources such as ponds and wells.”