In clinical trials with OPTISON, undesirable effects were reported as adverse events with the following frequencies given in the table below (Very common ≥ 1/ 10; Common (≥ 1/ 100 to < 1/ 10); Uncommon (≥ 1/ 1,000 to < 1/ 100); Rare (≥ 1/ 10,000 to < 1/ 1,000); Very rare < 1/ 10,000, not known (cannot be estimated from the available data)).