Katinka Hosszu led the way for Hungary by successfully defending her women's 200 metre individual medley crown to add to her 400m gold won on the opening day of competition, and then returning to anchor her team to silver in the 4x200m freestyle relay behind winners Italy. Evelyn Verraszto joined her on the podium after coming third in the 200m medley.
Hosszu was not the only women to win gold for the hosts on Thursday as Boglarka Kapas swam to victory in the 800m freestyle final. Eva Ristov came in third behind France's Coralie Bailey to ensure two Hungarians on the podium for that event.
Not to be outdone, the men also delivered for the hosts at the 2,000-capacity Debrecen Swimming Pool Complex.
Daniel Gyurta won the men's 200m breaststroke final before Laszlo Cseh and Bence Biczo claimed a one-two for the hosts in the 200m backstroke, with Cseh pipping his compatriot to the gold by 0.9 seconds.
Richard Bohus's third place in the Men's 50m backstroke final meant that the women's 100m backstroke was the only event of the night in which Hungary did not have a podium place.
Sophie Allen claimed Great Britain's second silver in 24 hours in Debrecen.
Allen followed fellow Stockport swimmer James Goddard with a second place in the same event - the 200m medley.
The 20-year old - who will join British team-mate Hannah Miley in the same event when she makes her Olympic debut in London - broke her own personal best and English record with a time of 2:11.49.
However, she was still more than half a second adrift of gold medallist Hosszu.