We have developed a novel method called loop-mediated isothermal amplification (LAMP) to detect Panax ginseng, the botanical source of Ginseng (Ginseng Radix), and to distinguish P. ginseng from Panax japonicus. Six allele-specific primers (two outer primers, two inner primers, and two loop primers) were designed based on the 18S ribosomal RNA gene sequence of P. ginseng, and LAMP was performed using those primers and total DNA extracted from P. ginseng as template. Amplifications were observed from approximately 30 min onwards at DNA concentrations of 0.5 to 10.0 ng. The presence of loop primers shortened the reaction time considerably. In contrast, in the reactions using total DNA from P. japonicus as template, no amplifications were observed. LAMP also enabled us to distinguish Ginseng from Japanese Ginseng (Panacis Japonici Rhizoma). LAMP was proven to be a rapid, highly sensitive, and specific method for the detection of P. ginseng and Ginseng.