Blessed Udoh, a medallist in the 48kg category, tested positive for diuretics, Zohir Bensohane, a Games official in charge of anti-doping control, told reporters.
Angola's Rola Nuno Nuno tested positive for an anabolic substance.
On the track, on the penultimate day of the Games, Kenya's world junior cross country champion Asbel Kiprop took the 1,500m gold ahead of two Algerians in a dramatic finish to the athletics programme.
Kiprop zoomed past Antar Zerguelaine and Tarek Boukensa in the last 30 metres to win in 3:38.97 with Zerguelaine second in 3:39.04 and Boukensa third in 3:39.18.
Tiny land-locked Botswana celebrated gold three times over.
They beat traditional sprinting champions Nigeria into second place in the men's 4x400m relay, winning gold in 3:03.16. Nigeria took silver in 3:03.99.
Kabelo Kgosiemang won the high jump with a clearance of 2.27 metres and Gable Garenamotse the long jump with a leap of 8.08.
Former world junior cross country champion Gelete Burika of Ethiopia notched decisive victory in the women's 1,500 metres, winning in 4:06.89.
In other action, Angola retained the men's basketball title after beating Egypt 56-50 at the Hydra Hall.
In Zeralda, Nigeria's Falcons thrashed South Africa's Banyana Banyana 4-0 in the women's soccer final.
Chiejine Ifeanyi Chukwu scored twice and Stela Mbachu and Perpetua Nkocha put the issue beyond doubt.
