A method of detecting Helicobacter pylori DNA in a stool sample, the method comprising: a) performing a nested PCR reaction comprising DNA isolated from a stool sample as a template and a first and second oligonucleotide primer set specific for amplifying H. pylori- specific target sequences in an H. pylori 23S rRNA gene in an amplification reaction, wherein the first oligonucleotide primer set comprises an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 1 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 1 and an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 2 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 2, wherein the second oligonucleotide primer set comprises an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 3 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 3 and an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 4 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 4, wherein the H. pylori-specific target sequence of the first oligonucleotide primer set is a nucleotide region of an H. pylori 23S rRNA gene corresponding to positions 1937-2793 of SEQ ID NO: 13 and at least part of said nucleotide region is amplified in the PCR reaction by the first oligonucleotide primer set, and wherein the H. pylori-specific target sequence of the second oligonucleotide primer set is a nucleotide region of an H. pylori 23S rRNA gene corresponding to positions 2482-2624 of SEQ ID NO: 13 and at least part of said nucleotide region is amplified in the PCR reaction by the second oligonucleotide primer set b) detecting H. pylori DNA in said stool sample when the H. pylori -specific target sequences are amplified. a) performing a nested PCR reaction comprising DNA isolated from a stool sample as a template and a first and second oligonucleotide primer set specific for amplifying H. pylori- specific target sequences in an H. pylori 23S rRNA gene in an amplification reaction, wherein the first oligonucleotide primer set comprises an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 1 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 1 and an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 2 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 2, wherein the second oligonucleotide primer set comprises an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 3 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 3 and an oligonucleotide primer comprising the nucleotide sequence as set forth in SEQ ID NO: 4 or consisting of at least 10 contiguous nucleotides present in the nucleotide sequence as set forth in SEQ ID NO: 4, wherein the H. pylori-specific target sequence of the first oligonucleotide primer set is a nucleotide region of an H. pylori 23S rRNA gene corresponding to positions 1937-2793 of SEQ ID NO: 13 and at least part of said nucleotide region is amplified in the PCR reaction by the first oligonucleotide primer set, and wherein the H. pylori-specific target sequence of the second oligonucleotide primer set is a nucleotide region of an H. pylori 23S rRNA gene corresponding to positions 2482-2624 of SEQ ID NO: 13 and at least part of said nucleotide region is amplified in the PCR reaction by the second oligonucleotide primer set b) detecting H. pylori DNA in said stool sample when the H. pylori -specific target sequences are amplified.