Colloidal gold is very attractive for several applications in biotechnology because of its unique physical and chemical properties. Many different synthesis methods have been developed to generate gold nanoparticles (AuNPs). Here, we will introduce these methods and discuss the differences between fabrication techniques. We will also discuss ecofriendly synthesis methods being developed to efficiently generate AuNPs without the use of toxic substrates. Finally, we will discuss the medical applications for AuNPs by highlighting the potential use of intact or functionalized AuNPs in combating bacterial infections.