Purple nutsedge roots (Cyperus rotundus L.) and fenugreek seeds (Trigonella foenum-graecum L.) have been traditionally used as food and to treat common ailments. After extraction by solid-phase microextraction (SPME), the chemical structure of the revealed volatile fractions was researched with gas chromatography with mass spectrometry (GC-MS). The determined substances of the C. rotundus were pentadecanolide (72.0%), palmitic acid (8.2%), 16-hydroxy-6-hexadecenoic acid omega lactone (4.4%), and (Z)-anethol (3.9%). Most of the identified compounds of the T. foenum-graecum were pentadecanolide (61.3%) and (Z)-anethol (16.5%). The C. rotundus showed good antifungal activity against the yeast strands of Candida albicans and Candida krusei. Minimum inhibitory concentration (MIC) numbers were 250 and 125 mu g/mL, respectively. However, the T. foenum-graecum seeds did not show any effect against the test microorganisms. The C. rotundus roots in particular exhibited good 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity with an IC50 number of 0.91 mg/mL.