Sanctions from individuals. The US did the opposite, and supported South Africa no matter what. Just like Israel - In both ways. Israel supported South Africa, and the US supported Israel. The dramatic sanctions against US citizens for refusing to buy from Israel and endorsing that people not buy from Israel are meant to prevent such a horrible thing as the fall of Apartheid from ever happening again.
This comment is mistaken. Many countries, including Japan from 1964, and eventually the US and UK, sanctioned SA officially. I doubt whether any boycott from individual US citizens had a serious economic effect compared to this.
