Quarterly report pursuant to Section 13 or 15(d)

Document And Entity Information

Document And Entity Information - shares
9 Months Ended
Jun. 30, 2023
Aug. 11, 2023
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Jun. 30, 2023  
Document Transition Report false  
Entity File Number 000-54986  
Entity Registrant Name ARCH THERAPEUTICS, INC.  
Entity Incorporation, State or Country Code NV  
Entity Tax Identification Number 46-0524102  
Entity Address, Address Line One 235 Walnut Street, Suite 6  
Entity Address, City or Town Framingham  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 01702  
City Area Code 617  
Local Phone Number 431-2313  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding (in shares)   3,094,370
Entity Central Index Key 0001537561  
Current Fiscal Year End Date --09-30  
Document Fiscal Year Focus 2023  
Document Fiscal Period Focus Q3  
Amendment Flag false