Prof Eloff is the first person in South Africa to receive a gold medal from both the Suid-Afrikaanse Akademie vir Wetenskap en Kuns and the Academy of Science of South Africa. He was honoured with the latest medal by ASSAF for excellence in the application of outstanding scientific thinking in the service of society.

Prof Eloff has made significant contributions in several areas that are important to society. These include areas such as soil fertility, toxic plant and cyanobacteria metabolism and ecology, as well as the use of compounds from plants as medicines and biopesticides.

He was appointed as the Executive Director of the eight National Botanical Gardens with the Head Office at Kirstenbosch. He changed the research culture of the organisation and established a new focus area of indigenous plant utilisation. He succeeded in combining the National Botanical Gardens, a statutory body, with the state department Botanical Research Institute to form the National Botanical Institute (NBI) and was appointed Director of Research of the NBI. After retiring he was appointed at the University of Pretoria where he started working on using compounds in plants to increase the quality of life of people in South Africa in the Phytomedicine Programme.

A major contribution to society was the training of previously disadvantaged students. Coming from a very large and relatively poor family and being the first family member ever to attend a university, he has empathy with struggling, especially among black students. His life motto: "Ubi caritas et amor, Deus ibi est" (Where there is caring and love, God is present) plays an important role in his work with students. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;}