The human mind strives to maintain equilibrium between memory and oblivion and rejects irrelevant or disruptive memories. However, extensive amounts of stress hormones released at the time of a traumatic event can give rise to such powerful memory formation that traumatic memories cannot be rejected and do not vanish or diminish with time: Post-traumatic stress disorder may then develop. Recent scientific studies suggest that beta-blockers stopping the action of these stress hormones may reduce the emotional impact of disturbing memories or prevent their consolidation. Using such an intervention could, in principle, help people who suffer from post-traumatic stress disorder, but the idea of doing so is controversial. I shall here discuss memory manipulation in this perspective.